Wa THE BOTANY
ICELAND
EDITED
BY
L. KOLDERUP ROSENVINGE
PH. D. AND
EUG. WARMING — eon aia
PH. D., SC. D.
PART I
\ 1. THE MARINE ALGAL VEGETATION BY HELGI JONSSON, jd 0 fe D.
ee te oie sear
(PUBLISHED BY THE AID OF ‘THE CARLSBERG FUND)
COPENHAGEN J, FRIMODT
LONDON JOHN WHELDON & CO.
1912
THE BOTANY ICELAND
EDITED
BY
L. KOLDERUP ROSENVINGE
PH. D.
AND —
EUG. WARMING
PH. D., SC. D.
PART I 1. THE MARINE ALGAL VEGETATION BY HELGI JONSSON, PH. D.
(PUBLISHED BY THE AID OF THE CARLSBERG FUND)
COPENHAGEN JP RIMO DS?
LONDON JOHN WHELDON & CO.
1912
PREFACE.
[ was mentioned in the preface to the “Botany of the Ferées’’ (Co- penhagen & London, 1901—1908) that, on the completion of that work, Iceland would be the one island among the dependencies of the Danish kingdom in the Atlantic which was in most need ofa thorough and systematic investigation as regards its botany, and the hope was expressed that this would be commenced as early as the year 1909. This hope has been so far realized that we, the undersigned, are now able to publish the first paper on the subject, viz. “The Marine Algal Vegetation” by Dr. HELa1 JOnsson of Reykjavik. Iceland, however, is so large compared with the Fero6es that the investigation will not only be far more difficult to carry out, but will also extend over a far longer period.
We hope that specialists in botany may be able, at short intervals, to visit the island and make collections and notes. Thus, even in 1910 a young bryologist, A. HESSELBO, studied the moss-vegetation — when he took the photographs, published in the present paper — and this summer he is again paying a visit to the island, after which he will prepare an account of the moss-flora and the moss-vegetation of Iceland.
Next summer we hope that a young lichenologist will be able to set to work in a similar manner, and will be followed by others, until the work can be completed with a general account of the vegetation and the plant-geographical position of the island.
L. KOLDERUP ROSENVINGE. EUG. WARMING.
COPENHAGEN, Aug. 1912.
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1.
THE MARINE ALGAL VEGETATION OF ICELAND
BY
HELGI JONSSON
PH. D.
WITH 7 FIGURES IN THE TEXT
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CONTENTS.
Page
UE OG AISES TE 6 op gal IIe a calor 26) CIRC DS 1 Pee nemie Mabie ALR 82 oe oa wes ba Wile oe RL a ide Was Nadie ee bs 5 II Life-conditions of the Marine Algal Vegetation....................4. Tr) MMC MNAtUEe OL ‘The COASE heats alls URS OPP bl 25
PoE CROCEAN St 7m i dente Coe RN OAs ara uRhh, OMS. Pie scaes <P an clans bie 27 Aumiinen Movements of the Ocean iH0 61652 nerd A Sale claw eee oa ea ee 27 ae Wh eImPerAavUre ORME VWALER HAI MYO RIAA TIA. a dine wie we we 32 Creare SaAlimIeyA Mr Poe Seah Me Be RUN wide ve Ro aN GMA s cea we we» en 40 mmbber ies. has oss SAI. LERAMTI aay Ds aed Pe Sa Mr 42 meg eTEDELALITGNe” se cients, Hae SEER aa ls ates, stk clale Nie Sake eke 42 EmMincwelumnidityers sont cathe tren RANE Ae To VS coed 44
C. Precipitation, Amount of Cloud, Foggy days, Wet days.......... 44
DEN EILOS 6 stisa' Me aies. 5 uted diaaete lak eh Sah BMA Hans tutte, ayancane At is 46
dey UGE TATE) TES cae ie ae OM ect RES Exe Medes og: Weer ee ts 0 Ps Sen 47
III The Horizontal Distribution of the Species and the Components of the
PMA M LOR Awe Sees tvs yin ehe ne Gate daa RER e Ri eee Sig! akvRalai des was 642% 48 iweeGomponents ot the rAlaal Flora vaso ccc. oote oh ee eee ee ew oe ees 58 AC SAT CEICe Croup tii: Leh Sey MD ee i Ede R Eee, 58 eR SO A OCLC AGO’ Poot 'cs.., sah sca eae ena ard Segue meee A Oe el ges ee es 59 Cr, ther boreal-Aretic- Group... ssi ees seb e ss EAEoR Ne PER BIR Oe 60 Drie Gold Bored le Groupits ick s Uh sa Sees Sie ahs el eyalnatesle wloales Hae, s 61 Bie lie: WW ania Onedle, GROUP joo, 22 sid cals ss ya el ene Bees & oh a Sed 62 PL ORISVICM ls OUMGARLESH s. 08 5.280 Ts ot ab oat bleu OaOnia Duid ds. eo ale Oe sa ale ee 66 IV Comparison with neighbouring Floral Districts ........................ 68 Ve, Dhe Vertical Distribution of the Spegies..c:.. 0... 6.5 ccc swan ve emes 80 Aes CAPER mE AthOral YZOME hamlets ope eee) oh ehacaph vr Aadal wh eee ede eae aealsas 85
B. The lower Littoral Zone and the Belt below down to a depth of PUD IO Me ORME ER ESE one Modi. cities at. Veen apse eG ewiishiin siete pee aiaeW @ 6 6 ¥ cash ses ak 88 MMe E SUIITCLOrAl SPECIES) ajc soc cPeo8 see Sod vow ee ha, olha ote eee awe ew N 91
MOE ee GITLES Obs GLO WGEEowe nian giciaie kon a's, oS aim ache ga ee bie wa ela aie eine we wees 92
VI Marine Algal Vegetation and Sea-grass Vegetation. 2. &: vcd os sce. 95 Account of the Marine Algal Vegetation and the Sea-grass Vegetation... 98 A> The, Marine Algal Vesetationwy. otc i. sent e eroie, cuant Gene <' diiaeeen a: “fhe: Littoral Zone ices tae eee se atie ices ons ae 99 aa. The Photophilous or strictly Littoral Communities....... 99 1. The Prasiola stipitata-association .............)..2 mee 100 2. The Gommunity of Filiform Alpe 7... 2... 4 102 3. The Community of Fucaces ).. 0005.4. 5.5>.. 7. cee 106 4. The Enteromorpha-association.. -9..... =... -)eeeee 120 5. The Acrosiphonia-association® ...5..:%.. 5 -.- eee 121 bb. The Shade-vegetation .2)...0405)..% «oon Hae Sis oe 123 6. The Hildenbrandia-association <<... .5: 2.2. . «2s 123 7. The Rhodochorton-association, the Sphacelarietum bri- tannici and the Polysiphonietum urceolate .......... 123 cc. “The Vegetation “of “Yide-Pools... 02. 2 a. ee le 125 b, ‘The ‘Semi-littoral Zome |... . os. <5 May oh. oe eee 128 8. The Monostroma-association. .«...-:....-. 4)... eee 129 9... The Chorda-association: : -o.d1.4% ossitiecee be oe 130 10.. The Community of /Rhodymenta:;;:.~.:\..4-- 4) eee 132 11. The Polysiphonia urceolata-association ..............., 133 12. The Community. of Corallina .......-.....5th ose 135 13. The Crustaceous alga-association...........6.-.+.ese see 138 ce... The: Sublittoral Zone ¢ 2.25366 vey ban onl tee 139 14. The Community of Laminariacez .................... 140 15, . The Desmarestia-association......)...... 2s. Heltete eee 151 16. The Deep-water Community of Floridee.............. 152 17. ‘The. Lithothamnion-association , ... .. 2.22), - ose eee 154 18. The Community of Crustaceous Alga.).).>5...c pee 155 B. The Sea-prass Vegetation 2... 0.255... bs. Ve. ons ot wenoh Oe 157 The >Zostera-association 3: <.)..0 cs. seueoe: sce beo eo eke 157 VII Differences in the Vegetation in East and South Iceland ............... 159 VIII Some Notes on the Biology of the Algz along the coast of Iceland..... 166 1: "Duration “of Life 1), foci e fis cus oe Oak Oho 166 2. Periodical Changes ©... 0 5 <6 so 169 3. Littoral Winter-vegetation of Reykjavik............... 180 Bibliagraphiy execu s.t. eet eek fee aes . eS 183
INTRODUCTION.
T is far from being a fact that the Marine Algal Flora and
Marine Algal Vegetation of Iceland can be regarded as sufficiently known; this does not apply in the same degree, however, to all parts of the coast. East Iceland, South Iceland and South-west Iceland are better known in this respect than North-west Iceland and North Iceland. Also, as is very natural, the littoral vegetation is better known than the sublittoral, as it is easier of access and may be investigated directly on the spot, while, as regards the sub- littoral vegetation, one has to be content with what is obtained from dredgings.
Very little has previously been written with regard to the marine algal vegetation of Iceland. Stré6mfelt, who travelled in Iceland in the summer of 1883, has treated the algal flora exhaustively (see Jonsson, 31) in his valuable work “Om Algevegetationen vid Is- lands kuster” (70) and has given a critical review of the older lite- rature of the marine algal flora of Iceland; but, on the other hand, he has dealt very briefly with the marine algal vegetation. He fol- lows Kjellman in dividing the vegetation in question into a litto- ral and a sublittoral vegetation. Str6mfelt found the littoral vege- tation poorly developed in many places — he records, however, a luxuriant littoral vegetation from Reykjavik, Eyrarbakki and Eskifj6rdur. The sublittoral vegetation is mentioned even more briefly, and is emphasized as being more uniform than the littoral as regards its distribution and the species which compose it. Str6m- felt does not make any definite statement regarding the elittoral vegetation, owing to his not having dredged in sufficiently deep water, but he considers it improbable that any vegetation worthy of notice occurs at that depth, as he did not find any rich vegeta- tion at a greater depth than 10—12 fathoms.
The reason why Strémfelt found the littoral vegetation on the north coast so poorly developed may be two-fold: it may result
The Botany of Iceland. I. 1
y H. JONSSON
from the drift-ice having remained at the coast during the whole summer of the previous year (1882), but it may also be due to the fact that, in this case, Stré6mfelt went by steamer from port to port, and could scarcely have obtained a thorough knowledge of the coast in as much as the steamer usually stops only a short time at each port.
Str6mfelt mentions the following algal formations: the Fucacee- formation which is reported from H6lmanes and Seley in E. Ice- land; the Laminaria-formation, under which a subvegetation of red alge is mentioned. Further, a Monostroma-vegetation is recorded as occurring near Ekifj6rdur at a depth of two fathoms on a sandy bottom, and a Halosaccion-formation at extreme low-water mark on Holmanes. Strémfelt expresses the opinion, moreover, that a Corallina-formation formed by Lithothamnion-species must exist, but he does not say anything definite regarding this point, as he received almost all the Lithothamnion-species from the fishermen (70, pp. 10, 11). The description of the vegetation is evidently based on observations made in places where Strémfelt stayed for a longer time, viz. Eskifjé6rdur and Reydarfjérdur in E. Iceland, and Eyrarbakki in S. Iceland. I have incorporated Strémfelt’s obser- vations with my own in my description of the vegetation.
Stré6mfelt, on the other hand, treats exhaustively of the dis- tribution of the species along the coasts. Thus he is the first to substantiate the existence of two floral districts in the sea on the coasts of Iceland: a cold-water flora in NE. Iceland and a warm- water flora in SW. Iceland. In a table he gives a summary of the distribution of the species along the coast of Iceland, and states whether they are found in the Norwegian Polar Sea, the North Atlantic and the Greenland Sea. He records 33 species as common to NE. Iceland and SW. Iceland, 33 species as growing in NE. Ice- land and absent from SW. Iceland, and 28 species as growing in the latter district and absent from the former. Thus 66 species in all are recorded from NE. Iceland and 61 species from SW. Iceland. Of the species given by Strémfelt as being found in or absent from NE. Iceland and SW. Iceland respectively, later investigations have proved that far the greater number are common to both places, but then, again, other species have been found which are characteristic of the different districts. |
My description of the algal vegetation along the coast of Ice- land is based mainly on my own observations, and further on
MARINE ALGAL VEGETATION 3
Stré6mfelt’s work, as well as on Ostenfeld’s observations. The latter mainly concern the littoral zone, and originate from E. Iceland (Hélmanes), SW. Iceland (Reykjavik, Njarévik) and S. Iceland (Stadur on the south side of Reykjanes).
Ostenfeld, moreover, has given information of the sublittoral vegetation of Myrakollur in NW. Iceland.
My own observations are drawn from various places encircling the whole of Iceland. In E. Iceland I have especially investigated Berufjérédur, Reydarfjérdur and Seydisfjéréur, and everything which is narrated of the algal vegetation from E. Iceland originates from these fjords. In N. Iceland I have examined Eyjafjéréur fairly ac- curately, from its innermost part to the submarine ridge off Hrisey, and I have, moreover, in the course of my journey, investigated the head of Hunafléi. When travelling by the mail steamer “Laura” round NW. Iceland I visited all the fjords from Skutulsfjéréur to Patreksfjéréur. I stayed only a short time in each fjord, as I ac- companied the boat from port to port, and was only able to dredge and investigate the littoral zone in the vicinity of the towns. In SW. Ice- land I have been at the south side of Breidifjéréur, and have dredged along the stretch of coast from Rést in Hvammsfjéréur to Hjallasand- ur, and have also examined the littoral zone over a far larger area, not only round Sneefellsnes but also in Dalasysla. Round Reykjavik I have dredged and investigated the littoral zone many times. In S. Iceland I have investigated the Vestmannaeyjar most thoroughly and have, in addition, dredged and examined the littoral zone at Eyrarbakki. All remarks concerning the algal vegetation of S. Iceland are based on observations: drawn from the western part of the south coast. The eastern part of the south coast from about Stokkseyri eastward is, as far as I know, a sandy coast, a “desert’’ devoid of algal vege- tation. I have not dredged further east than round the Vestmanna- eyjar, but on my trip through S. Iceland in 1901 I saw very few alge cast ashore, which may be regarded as a sure sign that a desert lies beyond, because, where algal vegetation exists, it is quite common, with a landward wind, for large, often astonishingly large quantities of algee to be thrown up on the shore. What might not be found then, on the south coast, where the swell of the Atlantic rolls up onto the flat shore, if any algal vegetation existed further out! Nor can it be expected that anything but a desert exists off this coast, as the bottom consists of sand, and the coast lies exposed to the sea, like the west coast of Jutland. Where, on the other hand, there
1%
4 | H. JONSSON: MARINE ALGAL VEGETATION
are rocks, there vegetation is sure to occur. At Vik in Myrdal near the southern point of Iceland there was, for instance, a poor vege- tation on the rocks.
When one considers how great is the extent of Iceland’s coast- line, one cannot expect this to be sufficiently elucidated as re- gards the distribution of marine algze by the few and scattered investigations which have been undertaken. For a long time, then, I nourished the hope of being able to undertake further investiga- tions, and therefore constantly deferred publishing a comprehensive description of the algal vegetation. Now, however, I have decided to delay no longer and hope in the future to be able to make a more extensive contribution in several respects towards the eluci- dation of the algal vegetation.
I. LIST OF THE MARINE ALGE.
HE following List of the Marine Algze of Iceland is extracted from my earlier publications (JO6nsson, 31, Bérgesen and J6énsson, 14) and from the paper by Henning Petersen (57) on the species of Ceramium. It gives only the names of the species with synonyms, their distribution in the different coastal districts and some new habitats. The limitation of species is unchanged except in the case of the genus Ceramium and in Clathromorphum circumscriptum (Strémf.) which is included in Clathromorphum com- pactum (Kjellm.) as proposed by Foslie. One species, Vaucheria spherospora Nordst. (Bérgesen and Jénsson, 14), is omitted from the list as it can scarcely be called a Marine Alga. Of Ceramium 5 species are added. Thus the number of species is: — 76 Rhodophycez 67 Pheophycez 51 Chlorophycez 6 Cyanophyces
Total... 200 species.
The coastal districts are the following (see the map, p. 7): —
East Iceland (E. Icel.), from Lonsheidi (Eystra horn) to Langanes.
North Iceland (N. Icel.), from Langanes to Hornbjarg (Kap Nord).
Northwest Iceland (NW. Icel.), from Hornbjarg to Latrabjarg.
Southwest Iceland (SW. Icel.), Breidifjordur and Faxafléi from Latra- bjarg to Reykjanes.
South Iceland (S. Icel.) from Reykjanes to Vestmannaeyjar and east- wards to Lonsheidi (Eystra horn).
In “The Marine Algez of Iceland” (Jénsson, 31) the district NW. Icel. is larger; it reaches from the inner end of Hunafldi to Latra- bjarg instead of as now from Hornbjarg to Latrabjarg. Localities from the part of the coast which stretches from Hunafldi to Horn-
6 H. JONSSON
bjarg are referred to NW. Icel., in the paper mentioned above, but in the present work (cf. Jonsson, 33, p.11) to North Iceland. These localities are: Hrutafjérdur, Prestsbakki, Kolbeinsa, Skalholtsvik, Kollafjardarnes, Broddanes and Grimsey in Hunafldi.
RHODOPHYCE#. BANGIOIDE#. Fam. Bangiacee.
Bangia fuscopurpurea (Dillw.) Lyngb., K. Roseny., 61, p. 831. Exicel: ~Neicel SW. Jcel..S. leek:
Porphyra umbilicalis (L.) J. Ag., K. Rosenv., 61, p. 830; P. laciniata Strémf., 70, p. 34.
Common in all parts of the coast of Iceland.
Porphyra miniata (Ag.) Ag., K. Rosenv., 61, p. 826; Diploderma m., D. tenuissimum, D. amplissimum Strémf., 70, p. 33. Found in all parts of the coast.
Porphyropsis coccinea (J. Ag.) K. Roseny., 65, p. 69; Porphyra coccinea JOénsson, 31. SW. Icel.: Reykjavik, S. Icel.
Conchocelis rosea Batters. Found in all parts of the coast.
FLORIDEZ.
Fam. Helminthocladiacee.
Chantransia virgatula (Harv.) Thur., K. Rosenv., 61, p. 824. NW. icel., SW. Icel.
Chantransia secundata (Lyngb.) Thur., K. Rosenv., 61, p. 824. Found in all parts of the coast.
Chantransia Alarize H. Jonsson, 31. SW. Icel., S. Icel.: Eyrarbakki.
Chantransia microscopica (Naeg.) Fosl. On Cladophora gracilis in the littoral zone. Thallus has long hairs. Published in Bérgesen and Jonsson, 14.
N. Icel.: Kolbeinsa.
The specimens mentioned under this name belong most probably to another species of Chantransia with a unicellular base.
MARINE ALGAL VEGETATION 7
Fam. Gigartinacee.
Chondrus crispus (L.) Stackh., Stromf., 70, p. 31.
NW. Icel. (cast ashore), SW. Icel., S. Icel.
Gigartina mamillosa (Good. et Wood.) J.Ag., Strémf., 70, p. 31. Found in all parts of the coast, common in SW. Icel. and S. Icel. Ahnfeltia plicata (Huds.) Fries, Strémf., 70, p. 31.
Cast ashore on N. Icel. and NW. Icel.. common in SW. Icel. and S. Icel.
a ayes : SSS SSS - SS Nioy ids iT ys Loacmad uty 56 LS San e Horndjarg 4q Crimsey eae < aera Melrakka= Langanes 2 Op yy 2 sljetta Vv Qa Oy a SN , pnp Z ; ay z wi wn ey \ Ki Be GS : ) Huna ‘ o ee < floi ¢ e Zz, t Reingrurs i: Latrabjarg Z Brodie) ® 9) j ee | ce ee yore pe) } Pees eo aS 7 Atos un nm Breidif}. 33 ye, Loa ai an or re ep Stykkisholnurs Sa res fy | Ce Sa. J TY barf | a} é ong ae Magee 2 Wig i! sD oe) @ : | wm : , fete Dpipioog ur | (SE 4s Tug \ os Lc Ru | . | tao) Maxat lon a : gor ? Lfyst whore = ~. rs) Hoalf- = Vestrakorn i ie ens S Re. 3 > rykjavik e Njarbvik ws « Eyrarbakhy, p - = Bs J \ ee ped a K XK aor T= d | SS | st Ves ORBIT EY J OF ra | ob 0 So Kilometer ibe Sis ei ee aes ia Fig. 1.
Phyllophora Brodizi (Turn.) J. Ag. *inferrupta (Grev.) K. Rosenv., GL, p21.
E. Icel., NW. Icel.
Phyllophora membranifolia (Good. et Wood.) J.Ag., Stromf., 70, p. 30. SW. Icel., S. Icel.
Actinococcus subcutaneus (Lyngb.) K. Rosenv., 61, p. 822. E. Icel., NW. Icel.
Ceratocolax Hartzii K. Rosenv., 62, p. 34. NW. Icel.
Fam. Rhodophyllidacee. Cystoclonium purpurascens (Huds.) Kiitz., Strémf., 70, p. 30. N. Icel., NW. Icel. (cast ashore), common in SW. Icel. and S. Icel.
8 H. JONSSON
Turnerella Pennyi (Harv.) Schmitz, K. Rosenv., 62, p. 29. E. Icel., N. Icel.
Euthora cristata (L.) J. Ag., Strémf., 70, p. 27. Common around the coast of Iceland.
Rhodophyllis dichotoma (Lepech.) Gobi, Strémf., 70, p. 26.
Common around the coast of Iceland.
Fam. Rhodymeniacee. Rhodymenia palmata (L.) Grev., Kjellman, 36, p. 147; Strémfelt, 70, p.27; R. pertusa Strémf., 70, p. 28. Very common around the coast of Iceland.
Lomentaria clavellosa (Turn.) Gaill.; Le Jol., Liste des Algues mar. de Cherb., p. 132, var. sedifolia Ag. S. Icel.
Lomentaria rosea (Harv.) Thur., Le Jol., Liste des Alg. mar. de Cherb., p. 131, Fig. Harv. Phyc. Brit., T. 358 and 301. S. Icel.
Plocamium coccineum (Huds.) Lyngb., Strémf:, 70, p. 27. S. Icel.
Halosaccion ramentaceum (L.) J. Ag., Kjellm., 36, p. 153; Strémf., 70, p. 29; H. scopula Strémf., 70.
Common around the coast of Iceland.
Fam. Delesseriacez.
Delesseria alata (Huds.) Lam., Strémf., 70, p. 24. SW. Icel., S. Icel. 3
Delesseria Baerii (Post. et Rupr.), J. Ag.: *corymbosa (J. Ag.) K. Rosenv., 61, p. 806.
There is a specimen of this plant in the herbarium of the Botanical Museum in Copenhagen; it is labelled “Islandia d. Morck.”
Delesseria sinuosa (Good. et Wood.) Lam., Strémf., 70, p. 24. Common around Iceland.
Delesseria sangvinea (L.) Lam.; Hydrolapathum s. Strémf., 70, p. 26. E. Icel.; rather common in SW. Icel. and S. Icel.
Fam. Bonnemaisoniacez.
Bonnemaisonia asparagoides (Wood.) C. Ag.
In the herbarium of the Botanical Museum in Copenhagen there are three specimens of this species, said to have been collected in Ice-
MARINE ALGAL VEGETATION 9
land. On one of the labels is written “misit Faber.” In Flora Danica T. 2579 a specimen of this plant is figured, regarding which Liebmann writes: “ad littora Islandiz pr. Reykjavik legit beatus Faber, cujus spe- cimina mecum communicavit cl. Hofman-Bang.”
Fam. Rhodomelacee. Pterosiphonia parasitica (Huds.) Falkenberg, Die Rhodomelaceen des Golfes von Neapel. Polysiphonia p. Kjellman, 36, p. 117; H. Jonsson, 31, p. 142. S. Icel.
Polysiphonia urceolata (Lightf.) Grev., Strémf., 70, p. 24. Common around Iceland.
Polysiphonia fastigiata (Roth) Grev., Strémf., 70, p. 24. NW. Iceland.; common in SW. Icel. and S. Icel.
Polysiphonia arctica J. Ag., K. Rosenv., 61, p. 800. E. Icel., N. Icel. and NW. Icel. common; SW. Icel.
Polysiphonia nigrescens (Huds.) Harv., Kjellman, 36, p. 126. N. Icel., SW. Icel.
Rhodomela lycopodioides (L.) Ag., Strémf., 70, p. 23. Common around Iceland. - Odonthalia dentata (L.) Lyngb., Strémf., 70, p. 23.
Common around Iceland.
Fam. Ceramiacez. Callithamnion Arbuscula (Dillw.) Lyngb., Strémf., 70, p. 32. Rather common in SW. Icel. and S. Icel. Callithamnion scopulorum C. Ag., Spec. Alg. (2), p. 176. SW. leel’ S: Icel: | Plumaria elegans (Bonnem.) Schmitz, Syst. Uebersicht der bisher bekannten Gattungen der Florideen, Flora oder allgem. bot. Zeit., 1889; Ptilota e. Kjellman, 36, p. 172. SW. leel-, “S: Icel: Ptilota plumosa (L.) Ag., Strémf., 70, p. 32. N. Icel.; common in NW. Icel., SW. Icel. and S. Icel. Ptilota pectinata (Gunn.) Kjellm., Strémf., 70, p. 32. Common in E. Icel., N. Icel. and NW. Icel.; rather rare in SW. Icel. Antithamnion Plumula (Ellis) Thur. 6 boreale Gobi, K. Rosenvy., 61, p. 787. A. boreale Strémf., 70, p. 32. E. Icel., N. Icel., NW. Icel., SW. Icel.
10 H. JONSSON
Antithamnion floccosum (Mill.) Kleen, Strémf., 70, p. 32. E. Icel., SW-tcel:;'S. teel:
Ceramium acanthonotum Carm., Kjelim., 36, p. 171. SWtcel:S: Teel:
Ceramium Deslongchampii Chauv., Petersen, 57, p. 108; Ceramium rubrum ex pte. Jénsson, 31. SW. Icel.: Reykjavik (L. Kolderup Rosenvinge, °/¢ 1886).
Ceramium fruticulosum Kiitz., Petersen, 57, p. 108. SW. Icel.: Seltjarnarnes (Helgi Jénsson, 78/3 1907).
Ceramium circinnatum Ag., Petersen, 57, p. 111; Ceramium rubrum ex pte. Jonsson, 31.
SW. Icel.: Stykkishélmur (Helgi Jénsson, 1!°/6 1897), Skerjafjérdur (Helgi Jénsson, !°/7 1905).
Ceramium arborescens J. Agardh, Petersen, 57, p. 112; Ceramium rubrum ex pte. Jénsson, 31.
N. Icel.: Hrisey (Helgi Jénsson, ?/7 1898); NW. Icel.: Latravik in Adal- vik (C. H. Ostenfeld, °/7 1896); SW.Icel.: Reykjavik (L. Kolderup Rosen- vinge, °/6 1886). |
Ceramium atlanticum Petersen, 57, p. 112; Ceramium rubrum ex pte Jonsson, 31.
SW. Icel.: Grétta (Helgi Jonsson, 17/6 1908), Hafnarfjérdur (Hjalmar Jensen, ‘/5 1890); S. Icel.: Stadur (C. H. Ostenfeld, 17/6 1896), Eyrarbakki (Helgi Jonsson, 34/5 1897), Vestmannaeyjar (Helgi Jonsson, 1/5 1897).
Ceramium rubrum (Huds.) Agardh, Petersen, 57, p. 113; Jénsson, Jl, ex pte. Nilicela NW. Teel: SW. dcels S-lcel:
Rhodochorton Rothii (Turt.) Naeg., K. Rosenv., 61, p. 791. E. Icel., N. Icel., NW. Icel., SW. Icel. (common), S. Icel.
Rhodochorton repens H. Jonsson, 31. S. Icel.
Rhodochorton minutum Suhr. Descr. in Reinke’s Atlas (59), Fig. Reinke’s Atlas T. 40. | SW. Icel.
Rhodochorton penicilliforme (Kjellm.) K. Rosenvy., Les Algues ma- rines du Groenland in Ann. Sc. nat., 7° Sér., XIX. E. Icel., N. Icel., NW. Icel., SW. Icel.
MARINE ALGAL VEGETATION 11
Rhodochorton membranaceum Magnus, K. Rosenv., 61, p. 794; P. Kuckuck, Beitrage zur Kenntniss der Meeresalgen, 1897. E. Icel., N. Icel., NW. Icel., SW. Icel.
Fam. Dumontiacee. Dumontia filiformis (Fl. Dan.) Grev., Stroémf., 70, p. 30. E. Icel., SW. Icel. (rather common), S. Icel. Dilsea edulis Stackh., Sarcophyllis edulis Kjellm., 36, p. 152. SW. Icel.
Fam. Squamariacee. Petrocelis Hennedyi (Harv.) Batters, A list of the Marine Algze ‘of Berwick-on-T weed. — N. Icel.; Hraunakrokur (O. Davidsson), NW. Icel., SW. Icel., S. Icel.
Cruoria arctica Schmitz, K. Rosenv., 61, p. 784. SW. Icel.
Cruoria pellita (Lyngb.) Fries, Kjellm., 36, p. 142. SW. Icel., S. Icel.: Eyrarbakki.
Peyssonellia Rosenvingii Schmitz, K. Rosenv., 61, p. 782; Hzema- tostagon balanicola Strémf., 70, p. 25? Petcel. N.tcel, NW. icel.. SW..Jcel,
Rhododermis parasitica Batters, A list of the Marine Alge of Berwick-on-T weed. NW. Icel., SW: Icel., S. Icel.
Fam. Corallinacez.
Lithothamnion glaciale Kjellm., Strémf., 70, p. 18. H, leet, N. Icel.;: SW. Icel.
Lithothamnion Ungeri Kjellm., 36, p. 91 excl. syn.; L. intermedium Strémf., 70, p. 19. | F_tcel., N: Icel. NW. Icel.
Lithothamnion tophiforme Unger, Foslie, The Norwegian forms of Lithothamnion, 1895, p.119; L. soriferum Strémf., 70, p. 18. E. Icel., N. Icel., SW. Icel.: Hvalfj6rdur (Horring), S. Icel.
Lithothamnion flavescens Kjellm., 36, p. 98. E. Icel.
Lithothamnion foecundum Kjellm., 36, p. 99. Bm Acel N: Teel.
12 H. JONSSON
Lithothamnion leve (Strémf.) Foslie, List of species of the Litho- thamnia p.7; Lithophyllum leve Strémf., 70, p. 21. E. Icel.; Nv Iecel.,. NW. Icel., SW Teeli;.S.iicel
. Lithothamnion Lenormandi (Aresch.) Foslie, The Norwegian forms of Lithothamnion, 1895, p. 150. SW. Icel.
Phymatolithon polymorphum (L.) Foslie, List of species of the Lithothamnia p.8; Lithothamnion polymorphum Strémf., 70, p. 19. Setcel: |
Clathromorphum compactum (Kjellm.) Foslie, Lithothamnion com- pactum Kjellm., 36, p. 101; Clathromorphum circumscriptum (Strémf.) Fosl., Lithothamnion circumscriptum Strémf., 70, p. 20.
In all parts of the coast.
Lithophyllum Crouani Fosl., List of species of the Lithothamnia, p10: N. Icel., NW. Icel., S. Icel.: Eyrarbakki.
Dermatolithon macrocarpum (Ros.) Fosl., Revised systematical survey of the Melobesiez, p. 21; Melobesia macrocarpa Strémf., 70, p. 23. SW. Icel., S. Icel.
Corallina officinalis L., Stromf., 70, p. 18. N. Icel., NW. Icel., SW. Icel., S. Icel.
Hildenbrandia rosea Kutz, Stromf., 70, p. 24. Common around the coast of Iceland.
PH OPHYCE.
Fam. Myrionemacee. Lithoderma fatiscens Aresch., emend. Kuck., Bemerk. I (47), p. 238. E. Icel., N. Icel., NW. Icel., SW. Icel.
Petroderma maculiforme (Wollny) Kuck., Bemerk. II (47), p. 382. N. Icel.
Ralfsia ovata K. Rosenv., 61, p. 900; 62, p. 94. N. Icel.: Husavik (Ove Paulsen), Prestsbakki; SW. Icel.
Ralfsia clavata (Carm.) Farl., Mar. Alg., p. 88; Reinke (59) Atlas T.5 and 6, figs. 14—20; Stragularia adherens Strémf., 70, p. 49, T. II, figs. 13—15.
E. Icel., N. Icel., NW. Icel., SW. Icel.
MARINE ALGAL VEGETATION 13
Ralfsia verrucosa (Aresch.) J. Ag., Reinke (59), Atlas T.5 and 6, figs. 1—13.
FE teels N: Teel SW: Icel.
Ralfsia deusta (Ag.) J. Ag., K. Rosenv., 61, p. 898.
E. Icel., N. Icel., SW. Icel., S. Icel.
Myrionema vulgare Thuret, Sauvageau, 66, p. 185.
N: Icel., SW. Icel.
Myrionema Corunne Sauvag., 66, p. 237.
S. Icel.
Myrionema globosum (Rke) Fosl., New or critical Norw. Alge, p. 17; Ascocyclus globosus Rke, 58, p. 46; Atlas (59) T. 17; aches globosus K. Rosenv., 62, p. 86, figs. 19—20.
E. Icel., N. Icel., NW. Icel., SW. Icel.
Myrionema feréense Borgs., 13, p. 424.
SW. Icel.
Myrionema Laminarie (K. Roseny.), Dermatocelis Laminariz K. Rosenv., 62, p. 89, fig. 21.
SW. Icel. 7
Ascocyclus islandicus H. Jonsson, 31, p. 149.
N. Icel.
Probably this species will prove to be identical with A. sph@rophorus Sauv., cf. J6nsson, 31, p. 151 and Kylin.! The last-named author writes that A. islandicus without doubt is identical with A. spherophorus, but he gives no particulars as to the chromatophores of the last-named species, I therefore must still regard the Icelandic plant as a distinct species.
Fam. Ectocarpacee.
Microsyphar Polysiphonie Kuck., Beitrage (48) p. 29.
NW. Icel., SW. Icel.
Streblonema ecidioides K. Rosenv., 61, p. 894; 62, p. 80; Phyco- celis ecidioides Kuck., Bemerk. I (57), p. 234.
E. Icel., N. Icel., SW. Icel.
Streblonema Stilophore Cr. var. cespitosa K. Rosenv., 61, p. 892.
Found in all parts of the coast.
Pylaiella littoralis (L.) Kjellm.; Ectocarpus littoralis, Kuck., 48, p. 7; Rosenv., 61, p. 881; Pylaiella littoralis, Pylaiella varia Kjellm., do, p. 83.
Common around the coast of Iceland.
1 Harald Kylin, Zur Kenntnis der Algenflora der Norwegischen Westkiste, «
Arkiv foér Botanik, Bd. 10, No. 1, 1910.
14 ; H. JONSSON
Ectocarpus tomentosoides Farl., New or imperfectly known Algze of U.S., reprint from Bull. Torr. Bot. Club, Vol. XVI, 1889, p. 11, T. 87, fig. 4; K. Rosenv., 61, p. 180; Gran, En norsk form af Ectoce. tomentosoides Farl., Christiania Vidensk. Selsk. Forhandl. for 1883, No. 17; Kuckuck, Ueber Polymorphie bei einigen Phzosporeen in Festschrift fiir Schwendener, p. 370, figs. 5—7.
E. Icel., N. Icel., NW. Icel.; common in SW Icel. and S. Icel. .
Ectocarpus tomentosus (Huds.) Lyngb., Hydr. Dan. (51) p. 132; Kjellman, 35, p. 73. |
SW. Icel., S. Icel.
Ectocarpus confervoides (Roth) Le Jol., Kuck., 48, p. 19; Kjell- man, 35, p.77, ex pte.; K. Rosenv., 61, p. 883, ex pte. Found in all parts of the coast.
Ectocarpus siliculosus (Huds.) Lyngb., Hydr. Dan. (51) p. 131; Kjellman, 35, p. 78; Kuck. 48, p. 15. N. Icel., SW. Icel.
Ectocarpus penicillatus (Ag.) Kjellm., 35, p. 76; E. confervoides f. penicillata Kjellman, 39, p. 79. E. Icel., N. Icel., SW. Icel.
Ectocarpus fasciculatus (Griff.) Harv., Kjellm. 35, p. 76. SW. Teel:;-S: Icel.
Ectocarpus Hinksiz Harv., Manual, p. 59; Phyc. Brit., T. 22; Sauvageau, Observations relatives 4 la sexualité des Phéosporées (Journal de Botanique, 1896).
S. Icel.
Fam. Elachistacez. Leptonema fasciculatum Rke, 58, p. 50; var. subcylindrica K. Rosenv., 61, p. 879. N. Icel., NW. Icel., SW. Icel.
Elachista fucicola (Vell.) Aresch., emend. K. Rosenv., 61, p. 878; E. fucicola Strémf., 70, p.49. a typica is the most common, / lu- brica (Rupr.) K. Rosenv. is rather common.
In all parts of the coast.
Fam. Sphacelariacee.
Sphacelaria britannica Sauvag., 67, p. 50. N. Icel., SW. Icel., S. Icel.
MARINE ALGAL VEGETATION £5
Sphacelaria radicans Harv., Sauvag., 67, p. 27, fig. 14; Reinke, 60, a AT hie. 15, Kuek., Bemerk. 1) (47), p: 229, fig. 4. Bowleels Neteel: SW. lIcel), Si Icel.
Sphacelaria olivacea Pringsh., emend. Sauvag., 67, p. 54.
NW. Icel., SW. Icel., S. Icel. .
Chetopteris plumosa (Lyngb.) Ktitz., Sauvag., 67, p. 44; Strémf., 70, p.52; K. Rosenv., 61, p. 903; Reinke, 59, Atlas T. 49—50.
E. Icel., N. Icel., NW. Icel., SW. Icel.
Fam. Punctariaceez. Omphalophyllum ulvaceum K. Rosenv., 61, p. 872, fig. 19. etcel, Punctaria plantaginea (Roth) Grev., K. Rosenv., 61, p. 871; 62, p. 71; Strémf., 70, p. 50. Ea tcel,N. icel.;.NW. Icel.
Litosiphon filiformis (Rke), Pogotrichum filiforme Rke (59), Atlas, p. 62, T. 41, figs. 13—25; K. Rosenv., 61, p. 869; Kuck., Ueber Poly- morphie bei einigen Phaeosporeen, Festschrift fiir Schwendener, p. 360.
Ealtcel. No icel:, SW. Icel.;\'S:Icel:
Isthmoplea sphezrophora (Harv.) Kjellm., 36, p. 276; Reinke (59), Atlas: T. 30; Pylaiella curta Foslie, Nye havsalger, in Troms6é Mu- seums Aarshefter, X, 1887, p. 181; Kjellman, 35, p. 85; Fosliea curta Rke, Atlas, p. 45.
melcelewN W..lcel..15 W. Icel., S_ lcel:
Stictyosiphon tortilis (Rupr.) Rke, Atlas, T. 31--32; K. Rosenv., 61, p. 868; Phloeospora tortilis Stroémf., 70, p. 51; Phloeospora sub- articulata Kjellman, 39, p. 78.
BY iceln aN, ice! 99N W: Icel.,, SW. Icel
Phzostroma pustulosum Kuckuck, Ueber einige neue Phezosporeen d. westl. Ostsee, Bot. Zeit. 1895, p. 182, T. VII; K. Rosenv., 62, p. 68, fig. 15.
E. Icel., NW. Icel., SW. Icel.
Scytosiphon Lomentaria (Lyngb.) J. Ag., K. Rosenv., 61, p. 863; 62, p.62; Strémf., 70, p. 50.
In all parts of the coast.
Phyllitis zosterifolia Rke, 58, p. 61; K. Rosenv., 61, p. 862. FE. Icel., NW: Icel., SW. Icel.,. S. Icel.
16 H. JONSSON
Phyllitis fascia (O. F. Mill.) Kiitz., K. Rosenv., 61, p. 862. Gathered in all parts of the coast.
Fam. Dictyosiphonacez. Coilodesme bulligera Stromf., 70, p. 48, T. II, figs. 9—12; K. Ro- senv., 61, p. 862; 62, p. 61, fig. 13. E. Icel., NW. Icel., SW. Icel.
Dictyosiphon Ekmani Aresch., Obs. phyc. 3 (7), p. 33. SW. Icel.
Dictyosiphon Mesogloia Aresch., Obs. phyc. 3 (7); Reinke, 58, p. 64. N. Icel.
Dictyosiphon Chordaria Aresch., Obs. phyc. 3 (7); Reinke, 58, p. 63; K. Rosenv., 61, p. 861; Coilonema Chordaria Strémf., 70, p. 51. E. Icel., SW. Icel.
Dictyosiphon corymbosus Kjellm., 36, p. 267; Strémfelt, 70, p. 51.
N. Icel.
Dictyosiphon hippuroides (Lyngb.) Kiitz.; Kjellm., 36, p. 268; Strém- felt, 70, p. 51.
N. Icel., NW. Icel., SW. Icel., S. Icel.
Dictyosiphon foeniculaceus (Huds.) Grey., Kjellman, 36, p: 269;
K. Rosenv., 61, p. 859; Strémf., 70, p. 52. E. Icel., N. Icel., NW. Icel., SW. Icel.
Fam. Desmarestiacee. Desmarestia viridis (Mull.) Lam., K. Rosenv., 61, p. 859; Dichloria viridis Strémf., 70, p. 51. Common around the coast of Iceland. Desmarestia aculeata (L.) Lam., Strémf., 70, p. 51; K. Rosenv., 61, p. $57.
Common everywhere along the coast.
Desmarestia ligulata (Lightf.) Lam. S. Icel.: Vestmannaeyjar (Ove Paulsen).
Fam. Chordariacez. Castagnea virescens (Carm.) Thur., K. Rosenv., 62, p. 58; Eudesme virescens Stromf., 70, p. 47. E. Icel., N. Icel., SW. Icel.
MARINE ALGAL VEGETATION 17
Leathesia difformis (L.) Aresch., Kjellm., 36, p. 252.
N. Icel., SW. Icel.
Chordaria flagelliformis (Miull.) Ag., Strémf., 70, p.47; K. Rosenv., 61, p. 854.
Common everywhere along the coast.
Fam. Chordacee. Chorda tomentosa Lyngb., Hydrophytologia Danica, p. 74; K. Rosenv., 61, p. 854. E. Icel., N. Icel., SW. Icel. Chorda Filum (L.) Stackh., K. Rosenv., 61, p. 853; Strémf., 70, p. 47. Be eel., \N. Icel., NW. Icel.,. SW. Icel.
Fam. Laminariacee. Saccorrhiza dermatodea (De la Pyl.) J. Ag.; K. Rosenv., 61, p. 850; Phyllaria lorea Stroémf., 70, p. 42. E. Icel., N. Icel., NW. Icel., SW. Icel. Laminaria saccharina (L.) Lam., Kjellman, 36, p. 229; 35, p. 24; Strémf., 70, p. 42. f. typica ; f. linearis J. Ag., Kjellman 36, p. 229; 35, p. 25; Strémf., 70, p. 42; Borgesen, 13, p. 451, fig. 85; f. latifolia Kjellm., 35, p. 26; Laminaria saccharina f. latis- sima Kjellm., 36, p. 230; Strémf., 70, p. 43? This species is common everywhere along the coast, especially the
principal form; f. linearis is rarer and f. latifolia is only met with in E. Icel. and NW. Icel. where it occurs gregariously.
Laminaria feroensis Borges., 13, p. 454. E. Icel., N. Icel. Laminaria nigripes J. Ag., emend. K. Rosenv., 61, p. 842. 6 atrofulva (J. Ag.) K. Rosenv. (I. c.); Laminaria discolor, La- minaria nigripes f. oblonga Strémf., 70, pp. 483—44. Ee. Icel. Laminaria digitata (L.) Lam., Kjellman, 36, p. 240; 35, p. 22; Strémf., 70, p. 45. f. genuina Le Jol. 49; Kjellman, 35, p. 23; f. stenophylla Harv. Phyc. Brit., T. 338; Laminaria stenophylla Strémf., 70, p. 45; J. Ag. De Lam., p. 18; Kjellm., 35, p. 24; f. cucullata Le Jol., 49.
F. genuina is common everywhere; f. sfenophylla: E. Icel., SW. Icel., S. Icel.; f. cucullata: E. Icel., NW. Icel.
The Botany of Iceland. I. D)
|
18 H. JONSSON
Laminaria hyperborea (Gunn.) Foslie, 20, p.42; Strémf., 70, p. 44; Laminaria Cloustoni Le Jol., 49, p.577; fig., Fosl., 20, T.1.
E. Icel., N. Icel., NW. Icel.; common in SW. Icel. and S. Icel.
Alaria Pylaii (Bory) J. Ag., emend. K. Rosenv., 61, p. 838; Alaria Pylaii and Alaria membranifolia Strémf., 70, p. 39.
f. typica K. Rosenv.; f. membranacea (J. Ag.) K. Rosenvy.
Common everywhere along the coast.
Alaria esculenta (L.) Grev., Kjellm., 36, p. 212; 35, p. 19; Alaria esculenta, Alaria linearis and Alaria flagellaris Strémf., 70, pp. 38— 41; A. flagellaris K. Rosenv., 62, p. 49. :
f. australis Kjellm.; f. fasciculata Stromf.; f. pinnata (Gunn.) Kjellm.
This species is exceedingly common everywhere along the coast.
Fam. Fucacee.
Fucus spiralis L., Kjellm., 36, p. 202; Strémf., 70, p. 35; Bdorge-
sen, 13, p.472; Fucus Areschougii Kjellm., 35, p. 11. f. typica; f. borealis Kjellm.
Ey icel N. icel- SW. tcel.s.icel:
Fucus inflatus L., M. Vahl, Fl. Danica (30), T. 1127; Foslie, Krit. Fortegnelse, Troms6 Mus. Aarshefter, IX, p. 109; Kjellm., 35, p. 11; K. Rosenv., 61, p. 834; Borgesen, 13, p. 465; Fucus evanescens Strémf., 70, p. 35; F. edentatus, F. furcatus and F. evanescens J. Ag., 3, p. 40; F.furcatus Kleen, 43, p. 29; F.edentatus De la Pyl., 15, p. 84.
f. typica. F.furcatus Kleen ex pte.; F.evanescens auct. ex pte.; F. edentatus De la Pyl.; fig. Flora Danica (30) T. 1127; Borgesen, 13, figs. 90 and 91. f. evanescens (C. Ag.) F. evanescens C. Ag., Sp. p. 92 et auct. partim. f. linearis (Huds.) K. Rosenv., 61, p. 834; F. linearis Hudson Flora anglica London 1762, Oeder Flora Danica (30) T. 351. f. eacposita. F. distichus Lyngb. Hydr. Dan. (51) p. 6, exclus. syn.; F. distichus a, robustior J. Ag. 3, p. 37, Kjellman 36, p. 210; F. inflatus f. disticha Borgesen, 13, p. 465. This species is common everywhere along the coast.
MARINE ALGAL VEGETATION 19
Fucus serratus L., Kjellm., 36, p. 196.
SW. Icel., S. Icel.
Fucus vesiculosus L., Kjellm., 36, p. 198; Strémf., 70, p. 34. f. typica, fig. Harv. Phyc. Brit. T. 204. f. turgida Kjellm. f. spherocarpa J. Ag.
This species is common everywhere.
Pelvetia canaliculata (L.) Dec. et Thur., Strémf., 70, p. 38. SW. Icel., S. Icel.
Ascophyllum nodosum (L.) Le Jol., K. Rosenv., 61, p. 832; Ozo- thallia nodosa Strémf., 70, p. 34. Common along the coast.
CHLOROPHYCE.
Fam. Protococcacee. Chlorochytrium Cohnii Wright, K. Rosenv., 61, p. 963. SW. Icel. |
Chlorochytrium inclusum Kjellm., 36, p. 320, T. 31, figs. 8—17; K. Rosenv., 61, p. 963; 62, p. 119. Reteel, N. Icel., NW. Icel., SW. tcel.
Chlorochytrium dermatocolax Rke, 58, p. 88; K. Rosenv., 61, p. 964; Svedelius, 71, p. 72. Ne lcels,. SW: Icel.
Chlorochytrium Schmitzii K. Rosenv., 61, p. 964; 62, p.119. SW. Icel.
Codiolum Petrocelidis Kuck., Bemerk. (47), p. 259, fig. 27. SW. Icel.
Codiolum gregarium Al. Braun, Algarum unicellularum genera nova et minus cognita, Lipsiz, 1855, p.19; Boérgesen, 13, p. 517.
E. Icel. |
Codiolum pusillum (Lyngb.) Kjellm., Bérgesen, 13, p. 518; Vau- cheria pusilla Lyngb. Hydr. Dan. 51, p. 72, T. 22.
N. Icel. |
Fam. Ulvacee. Percursaria percursa (Ag.) K. Rosenv., 61, p. 963.
SW. Icel. 2%
20 H. JONSSON
Enteromorpha aureola (Ag.) Ktitz., Tab. phyc., Vol. VI, T. 40, II; Ulva aureola Ag. Ic. alg. europ. (1), T. 29; Capsosiphon aureolus Gobi; Ilea fulvescens J. Ag., Ulvacez p.114; ? Solenia fulvescens Ag., 2, p. 420; Enteromorpha quaternaria Ahlner in Wittr. et Nordstedt Alg. exsicc., Nos. 138 and 139.
N. Icel.
Enteromorpha Linza (L.) J. Ag., Ulva enteromorpha a, lanceolata Le Jol., 50, p. 42. |
SW. Icel., S. Icel.
Enteromorpha intestinalis (L.) Link., emend. K. Rosenvy., 61, p. 957; Bérgesen, 13, p. 487.
f. genuina K. Rosenv. I. c. p. 957; Enteromorpha intestinalis Strémf., 70, p. 52.
f. micrococca (Kiitz.) K. Rosenv. 1. c. p. 957.
f. compressa (L.) K. Roseny. 1. c. p. 958; Enteromorpha compressa f. typica and E. complanata f. subsimplex Strémf., 70, p. 53.
f. minima (Naeg.) K. Rosenv., |. c. p. 959; Enteromorpha minima Strémf., 70, p. 53.
f. prolifera (O. F. Miller) Bérgesen, 13, p. 490. Enteromorpha prolifera K. Rosenv., 61, p. 960.
This species is common everywhere along the coast.
Enteromorpha clathrata (Roth) Grev., Kjellm., 36, p. 287; Ulva clathrata Le Jol., 50, p. 48 (partim) ; Enteromorpha compressa f. race- mosa Strémf., 70, p. 53.
E: Icel., N. Icel., SW. Icel., S. Icel.
Monostroma groenlandicum J. Ag., K. Rosenv., 61, p. 954, fig. 53. E. Icel., N. Icel., NW. Icel:
Monostroma Grevillei (Thur.) Wittr., emend. K. Rosenv., 61, p. 946.
var. typica K. Rosenv. |. c. Monostroma Grevillei Wittr., 76, p. 57; Strémf. 70, p. 54 partim (e specim.).
var. arctica (Wittr.) K. Rosenv. l. c. Monostroma arcticum Wittr., 76, p. 44; Monostianet latis- simum Strémf., 70, p. 54.
var. intestiniformis K. Rosenv. 1. c. Enteromorpha intestinalis Strémf., 70, p. 58 partim (e spec.).
Var. typica and var. arctica are common along the coast; var. inte- stiniformis: E. Icel., SW. Icel.
MARINE ALGAL VEGETATION 21
Monostroma undulatum Wittr. 76, p. 46, T. III, fig. 9; K. Rosenv., 61, p. 945; Monostroma Grevillei Strémf., 70, p. 54 partim (e specim.).
In all parts of the coast.
Monostroma fuscum (Post. et Rupr.) Wittr., emend. K. Rosenv., 61, p. 940; M. Blyttii, Strémf. 70, p. 54.
f. typica is common along the coast; f. grandis.: E. Icel., N. Icel.
Ulva Lactuca L., K. Rosenv. 61, p. 839; Strémf., 70, p. 54. N. Icel., NW. Icel., SW. Icel., S. Icel.
Fam. Prasiolacez. Prasiola polyrrhiza (K. Rosenv.). Gayella polyrhiza K. Rosenv., 61, p. 936; Prasiola crispa subsp. marina Bérgesen, 13, p. 482;
Prasiola crispa f. submarina Wille, 73, p. 13. SW. Icel., S. Icel.
Prasiola furfuracea (Mert.) Menegh. Imhauser, 29, p. 266; Foslie Contrib., I, p. 127; Borgesen, 13, p. 486. E. Icel., N. Icel., SW. Icel.
Prasiola stipitata Suhr; Imh4user, 29, p. 272; Kjellman, 36, p. 303. leek: N: leel:, SW. Icel.,.S.Icel.
Fam. Ulothricacee.
Ulothrix consociata Wille, 73, p. 25. var. islandica H. Jénss. N. Icel.
Ulothrix subflaccida Wille, 73, p. 29. E. Icel., N. Icel.
Ulothrix pseudoflacca Wille, 73, p. 22, T. II, figs. 64—81. E. Icel., SW. Icel., S. Icel.
Ulothrix flacca (Dillw.) Thur., K. Rosenv., 61, p. 935, fig. 44; Wille, 73, p.18, T. I—II, figs. 54—63.
Common around the coast of Iceland.
Fam. Cheetophoracee. Pseudendoclonium submarinum Wille, 73, p. 29, T. III, figs. 101—134. _E. Icel.
Entoderma Wittrockii (Wille) Lagerh., K. Rosenv., 61, p. 934. N. Icel., SW. Icel., S. Icel.
22 H. JONSSON
Acrochete parasitica Oltm. Bot. Zeit. 1894, p. 208; K. Rosenv., 62, p. 114. SW. Icel.
Acrochete repens Pringsh., Beitrage p. 2, T. II; Huber, 28, p. 306.
NW. Icel.
Bolbocoleon piliferum Pringsh., Beitrage p. 2, T. Il; Huber, 28, p. 308, pl. 13, figs. 8—12.
E. Icel., N. Icel., NW. Icel.
Fam. Mycoideacee.
Ulvella fucicola K. Rosenv., 61, p. 926, fig. 40. Pseudopringsheimia fucicola (Rosenv.) Wille in Engler u. Prantl: Die natirlichen Pflanzen- familien, Nachtrage zu I. Theil, Abtheil 2, p. 89. :
E. Icel., N. Icel., SW. Icel., S. Icel.
Pringsheimia scutata Rke, 58, p.81, Atlas T. 25. NW. Icel., SW. Icel.
Ochlochete ferox Huber, 28, p. 291, T.X; K. Rosenv. 61, p. 931, fig. 41. N. Icel.
Fam. Cladophoracee. Urospora mirabilis Aresch., K. Rosenv., 61, p. 918, fig. 35; 62, p. 106.
Common along the coast.
Urospora Hartzii K. Rosenv., 61, p. 922, fig. 38. E. Tcel.,, SW. Icel: *S: Icel:
Urospora Wormskioldii (Mert.) K. Rosenv., 61, p. 920, fig. 36.
In all parts of the coast.
Cheztomorpha tortuosa (Dillw.) Kleen, K. Rosenv., 61, p. 917. E. Icel., N. Teel; “SW.1cel.
Chetomorpha Melagonium (Web. et Mohr) Kitz., K. Rosenv., 61, p. 917; Strémf., 70, p. 55.
Probably common along the coast of Iceland.
Rhizoclonium riparium (Roth) Harv., K. Rosenv., 61, p. 913; 62,
p. 103. f. polyrhiza K. Rosenv., 1. c. p. 913.
f. valida Fosl., K. Rosenv., 1. c. p. 915. f. implexa (Dillw.) K. Rosenv., I. c. p. 915. FE. Icel., N. Icel., SW. Icel.
MARINE ALGAL VEGETATION 23
Spongomorpha vernalis (Kjellm.) Wille, Acrosiphonia vernalis Kjeilm., 41, p. 82. SW. Icel.
Acrosiphonia albescens Kjellm., 41, p. 55, T. IV, fig. 21; Bérgesen, 13, p. 507, fig. 103; Spongomorpha arcta Strémf., 70, p. 54, ex pte.
Common along the coast of Iceland.
Acrosiphonia incurva Kjellm. 41, p. 61. Common along the coast.
Acrosiphonia hystrix (Strémf.) H. Jénss., 31.
f. typica H. Jénss., Spongomorpha hystrix Strémf., 70, p. 54, Cladophora diffusa Strémf., 70, p. 55 ex pte. (e specim.); Cladophora (Spongomorpha) arcta y hystrix K. Rosenv., Oke p: 907.
f. littoralis H. Jénss.
Beteel, ON» Icel;.NW:1céel., SW. Icel.
Acrosiphonia flabelliformis H. Joénss., 31.
S. Icel. :
Acrosiphonia penicilliformis (Fosl.) Kjellm., 41, p. 80 forma.
Eieteel 6.
Cladophora rupestris (L.) Kiitz., K. Rosenv., 61, p. 909; Strémf., 70, p. 55.
N. Icel., NW. Icel., SW. Icel., S. Icel.
Cladophora hirta Kiitz., Kjellm., in Wittr. et Nordstedt Exsicc., No. 1041.
SW. Icel., S. Icel.
Cladophora sericea (Huds.) Aresch., 8, p. 194, forma.
Ne lee eS. tcel:, Ss Icel.
Cladophora glaucescens (Griff.) Harv., Phyc. Brit. T. 196; Le Jol. Alg. mar. d. Cherb. Exsicc., 66.
SW. Icel.
Cladophora gracilis Kiitz., Kjellm. in Wittr. et Nordstedt Exsicc., No. 1040.
Em téeleN: Tcel., SW. Icel.
Fam. Gomontiacez. Gomontia polyrrhiza (Lagerh.) Born. et Flah. sur deux nouv. gen. d’Algues perfor. Journ. de Bot. Tom. II, 188, p. 163. E. Icel., N. Icel., NW. Icel., SW. Icel.
24 H. JONSSON: MARINE ALGAL VEGETATION
Fam. Phyllosiphonacee. Ostreobium Queketti Born. et Flah., Sur quelques plantes vivant dans le test calcaire des mollusques, p. 15, pl. IX, figs. 5—8. E. Icel., N. Icel., NW. Icel., SW. Icel.
CYANOPHYCER.
Fam. Chamesiphonacee.
Pleurocapsa amethystea K. Rosenv., 61, p. 967, var. E. Icel., N. Icel.; common in NW. Icel., SW. Icel. and S. Icel.
Fam. Oscillatoriacee. | Plectonema norvegicum Gomont, Bull. de la Soc. bot. de France, tome XLVI, 1899. N. Icel.
Phormidium autumnale (Ag.) Gomont, emend. Johs. Schmidt, 68, pp. 348 and 410. : E-icel:
Spirulina subsalsa Orsted, Beretning om en Excursion til Trin- delen, Krogyers Tidskrift 3. Bd., pp. 566, 1842. N: cel. “S: Teel.
Fam. Rivulariacee. Calothrix scopulorum (Web. et Mohr) Ag., emend. Johs. Schmidt, 68, pp. 390 and 414. E. Icel., N. Icel.
Rivularia atra Roth, Catalecta botanica, III, p. 340, 1806. SW. Icel.
I]. LIFE-CONDITIONS OF THE MARINE ALGAL VEGETATION.
1. THE NATURE OF THE COAST.
HE coast of Iceland consists partly of rock and partly of sand.
The rocky coasts are rich in algal vegetation, while the sandy coast is most frequently a “desert.” Here and there vegetation may be found, however, on the sandy coast, where this is not exposed to violent movement during any length of time. The vegetation then consists of short-lived species.
The Rocky Coast. This abounds in indentations of various size: inlets, fjords and bays. The size of the fjords varies greatly; for example, the largest, Faxafléi, is ten geographical miles long — and twelve geographical miles broad, and Breidifjérdur is eighteen geographical miles long and ten geographical miles broad. The smaller fjords, on the other hand, are short and narrow indenta- tions. Thus, owing to the indentations on the coast, the exposure is apt to vary greatly. The extreme points and the outer portions of the fjords have, as a rule, an exposed position, while in the interior of the fjord the water is generally calm.
The rocks on the coast consist of basalt; in some places, how- ever, tuff-coasts exist, and especially on the south coast. The fjord- coasts of Iceland, which comprise South-west, North-west, North and East Iceland, are mainly composed of basalt. The basalt varies considerably but, as far as I have seen, it has no significance as regards the distribution of the species, and no difference is seen, for example, in the vegetation on the dolerite and the ordinary basalt coasts. What is of prime importance to the vegetation is not the rock itself but the nature of its surface. The surface is, as a rule, very uneven, being eroded by water, weather and wind, and furrowed by numerous fissures. Its nature is, therefore, such that the alge can easily attach themselves to it.
26 H. JONSSON
The rocky coast is, as a rule, of solid rock, consisting of preglacial basaltic lava. Postglacial basaltic lava is found, nevertheless, in some places, as for example on Sneefellsnes. In many places, large stretches of the coast are covered with debris (Urd) from the mountains. Where the debris or the new lava predominates the surface is ge- nerally very uneven, and one then finds distinct elevations with - large and small depressions interposed; such a coast is usually covered with an abundant and multifarious algal vegetation, if the conditions are in other respects favourable to the existence of alge.
There is no range of skerries (Skzrgaard) as there is, for example, on the coast of Norway. Yet a number of islands and rocks occur in the fjords, especially in Breidifjérdur. In this fjord are found indications of a range of skerries running parallel with the coast and along a considerable stretch of it, and marking the outward limit of the Zostera-vegetation.
The Sandy Coast. Almost the entire coast of S. Iceland is sandy shore or gravel shore. As a rule, such bottoms afford a mobile substratum because each wave which breaks on the beach shifts the particles backwards and forwards. A sandy coast is also met with, here and there, in other parts of the country, but is then found, as a rule, alternating with rocky parts; thus, the sandy or gravelly shore is often predominant at the head of small indentations which at the sides are bounded by projecting masses of rocks.
Clayey Shore is also found fairly frequently in the interior of the fjords. ‘OLE
The rocky coast is, as a rule, abundantly overgrown, and this is frequently the case also with the sublittoral gravel-bottom, while the sand and gravel bottoms laid bare periodically by the shifting tide are not, as a rule, overgrown, and, in any case, only with short- lived species. On clayey and muddy bottoms, on the other hand, algee are seldom or never found, while Zostera often covers such a bottom and forms submarine “green meadows.”
Despite the small “desert” areas, one may say that the coasts are covered with a zone of continuous algal vegetation — if we ex- clude the eastern portion of S. Iceland. This algal zone varies greatly in width, accommodating itself to the precipitousness of the coast. In a bay as shallow as Faxafldi the algal vegetation has a great extension seawards, while it is far more limited, for example, on the steeply descending submarine declivities in the fjords of the east coast.
MARINE ALGAL VEGETATION za
2. THE OCEAN.
As regards the ocean, the chief points are its movements, tem- perature and salinity.
A. The Movements of the Ocean.
These are — tides, waves and currents. All these movements of the ocean are of very great importance to the life of the alge.
a. Tides. By the alternate rise and fall of the tide a part of the shore is laid bare, and the vegetation growing there must then be capable of maintaining life in the air for a longer or shorter period. Those plants which grow highest up in the zone thus left dry, are exposed during the greater part of the period between the one flood-tide and the next, or for about 10—11 hours in every 12. The plants occurring lowest down in the zone, on the other hand, are not exposed during spring-tide for more than one hour in every 12, and they are submerged the whole time during neap-tide. The upper limit of the algal vegetation is, moreover, dependent on how high the tide rises, i. e. the height of the flood-tide.
The Height of the Flood-tide. The following data regarding the height of the flood-tide are taken from “Den islandske Lods” (1903) and from the alterations and additions to it which have been published. The height of the flood-tide is greatest in SW. Iceland and least in E. Iceland. The height of the flood-tide at spring-tide is recorded as being about 14 feet from Reykjavik (SW. Iceland), 10—11 feet from NW. Iceland, 5—51/2 feet from the north coast and 5 feet from E. Iceland.
In many places there is a great difference as regards the height of the flood-tide during the spring and neap tides. To illustrate this more fully I give the following figures from some localities on the different parts of the coast: —
Spring-tide Neap-tide
South Iceland, Vestmannaeyjar ....<.....6. 8—10 feet 4 feet = Ei aD Ka iss, stcashawes vay shes Oe) Gs 10:7 "= Gh iis South-west Iceland, Reykjavik ............. cir. 14 - 4 - = Stykkisholmur 00). acc. LA = 6 - North-west Iceland, Dyrafjérdur ........... 1 5-6 - North) Iceland, Akureyri’. <4... 2. ...<24.6++- 51/2 - 11/2 - Bastetceland, DyapivOeur ..’< <p )bel wince eh = - 71/2 - 21/2 -
From Ellidaey near Stykkishédlmur in SW. Iceland the height of the flood-tide during spring-tide is recorded as being 14 feet and
28 H. JONSSON
during neap-tide 7 feet, and it is also recorded from the latter place that the low-water at neap-tide lies about 3 feet above that at spring-tide.
When extraordinary conditions prevail the height of the flood- tide may be still greater; thus, 18—19 feet has been recorded from Reykjavik and 18 feet from Stykkisholmur.
- From this it is seen that the height of the flood-tide varies greatly, which must necessarily affect the algal vegetation in several respects, especially as concerns the upper limit of its growth. Thus there is a great difference in the highest flood-mark (at spring-tide) and in the lowest flood-mark (at neap-tide). The tidal wave or the tide, moreover, shows irregularities, because neither the highest flood-mark (spring) nor the lowest flood-mark (neap-tide) is constant. The limit of the flood-tide fluctuates perpetually between a high- mark and a low-mark. The high-mark or the highest limit of the flood-tide is seen distinctly on rocky coasts from the action of the sea on the rock. On flat coasts, the high-mark can be distinguished by detached algze and various other bodies which accompany the tidal wave and remain at the highest level reached by the water. This high-mark lies considerably higher than the upper limit of the algal vegetation.
The low-mark is not as easy to distinguish as the high-mark, but it will almost coincide with the upper limit of the Pelvetia- — Fucus spiralis association. Above this the Bangia association (Ulo- thrix, Bangia, and others) is found, the extreme limit of which will almost coincide with an average water-level which, however, does not lie midway between low-mark and high-mark, but rather nearer the former. The upper limit of the algal vegetation thus lies some- what above the limit of the flood-tide at neap-tide. The same rule holds good, of course, on a very exposed coast. That the place is exposed means that there is a heavy swell, which causes the sea to rise higher up on the coasts, both at neap-tide and at spring-tide.
By the upper limit of the marine algal vegetation is meant that boundary line above which marine alge do not occur in the form of associations; on the other hand, no account is taken of single individuals or groups of individuals being found higher up, in crevices or pools, as such an occurrence must be considered accidental, — because they are carried up to this height with the high water or by far-reaching breakers. They do live, of course, but do not thrive, and have evidently gone beyond their real area of distribution. In
MARINE ALGAL VEGETATION 29
this respect, however, those species should be excepted which can grow both in salt and in fresh water, as for example, Enteromorpha intestinalis (the principal form) and others. Naturally, such species cannot be taken into account when defining the upper limit of srowth of marine algal vegetation.
If we compare the upper limit of the marine algal vegetation in Iceland with the same limit in Greenland it appears that they agree almost completely, as Rosenvinge (63, p. 89) sets the limit in Greenland almost at flood-mark at neap-tide. On the other hand there seems to be an incongruity with the Ferées, as Bérgesen (11 and 12) sets the limit far above highest flood-mark in exposed places and almost at uppermost flood-mark in sheltered places.
If we institute comparisons with more distant coasts, for instance with the west coast of Sweden, the algal vegetation of which has lately been described by Kylin (43), we find that, as regards the upper limit, the case is the same as in Iceland, that is, the upper limit is coincident with an average water-level which lies higher in exposed places than in sheltered ones.
In Iceland, indeed, on a very exposed coast, marine algz can be found rather high up, and if the sea is smooth and calm they may appear to be rather far away from the water; but on returning to the same place when the sea is in motion we see that it washes over them, and we no longer think it strange that they grow in so high a position. While the marine algal vegetation, as mentioned before, only extends upwards to an average water-level, it frequently happens on flat coasts that the land-vegetation is sub- merged at spring-tide. This occurs both in the interior of the fjords and on the lower islands, and may generally be distinguished by the appearance and the components of the vegetation; marine alge, however, do not occur among such vegetation.
Some phanerogams, e. g. Atriplex, Mertensia, Cakile, etc., also grow below the upper limit of the littoral zone. According to Ro- senvinge it happens in Greenland also that the land-vegetation is submerged at spring-tide.
b. The Swell. Here, those inequalities in the surface of the ocean which in every-day language are called waves, and that volume of water which, with a sea-wind is forced in towards the land, are treated collectively. The volume of water which is driven towards the coast by a sea-wind raises the water-level. While the tidal wave rises, the sea moved by the wind works together with
30 H. JONSSON
it, but when the water falls it counteracts the tidal wave; this circum- stance is of great importance on exposed coasts where the wind blows frequently, as it shortens the period of desiccation. These move- ments in the sea are naturally somewhat irregular, but the irregu- larities are quite equalized in the long run, and therefore the effect of these movements may very well be regarded as constant. The high-mark which the water leaves on the coasts is due to the tide and to these movements jointly.
A frequent sea-wind has a favourable eaeel on the vegetation in the zone laid bare by the tide, as mentioned above, but where a frequent land-wind is blowing the effect is the reverse, as this counteracts the rise of the tidal wave and accelerates its fall, whereby the period of desiccation is prolonged. 7
The effect of the waves beating on the algz is great. In ex- posed places, that is in places where the swell is heavy, the plants must be able to withstand the drag of the waves. The species which grow in these places therefore have a tough, leathery and narrow frond, whereas species in quiet waters have a delicate frond, often broad and brittle. The consistency of the frond thus accom- modates itself to the force of the beat of the waves, and in partially exposed places, or in places where the beat of the waves is not strong, but yet fairly considerable, we find the consistency of the frond to be about midway between what it is in exposed and in calm places.
Like all other movements of the sea, the waves also are of great importance to the algal vegetation by the fact of their con- stantly providing fresh particles of water.
c. Currents (Fig. 2). Along the coast of Iceland the warm water of the Atlantic Ocean meets the cold water of the Arctic Ocean. The Gulf Stream washes the south coast of the country and sends an arm northward along SW. Iceland and NW. Iceland, and along the entire north coast warm water can be traced (the eastern arm of the Irminger Current) to Langanes; and from thence the arm turns toward the south along the coast of E. Iceland (Nielsen, 52, p. 13), where it mixes with water from the East Iceland polar cur- rent, which comes from the Norwegian Sea (Helland-Hansen and Nansen, 27, p. 287, where the current is called the East Iceland Arctic Current). In this manner characteristic coast-water arises at E. Iceland. Regarding this Nielsen (52, p.13) writes that the Irminger Current “gives the waters over the coast shoal of East
MARINE ALGAL VEGETATION ol
Iceland a physiognomy different from that of the surrounding sea, the distribution of temperature being different even if the tempera- ture is not in any important degree higher than in the East Ice- landic polar current itself.”
The conditions of the currents in N. and E. Iceland are evidently very complicated, and only the direction of the current of the warm water has been given above in outline, but as the observations are so few it is difficult to form an opinion as to how the condi-
Fig. 2. Map of Currents.
(Helland-Hansen and Nansen.)
tions of the currents along these coasts vary in other respects from year to year or according to the seasons.
Further, other current-movements occur in the coast-water which may be deemed to be of importance to the vegetation, that is, such movements as are due to varying specific gravity. In the summer (Nielsen, 52, p. 8) the surface-water along the coast is lighter on account of its mixing with fresh water. A surface- current from the coast outwards then arises, and an under-current from the depth towards the coast. In the winter the surface-water along the coast becomes heavier owing to cooling, and sinks. Then a surface-current from the ocean towards the coast arises, and an under-current from the coast towards the depth.
52 H. JONSSON
B. The Temperature of the Water.
a. The temperature of the ocean around the coasts is not suf- ficiently known, and consequently the mean values cannot be given. I give, therefore, as an example, some actual measurements, as even these may be instructive in several respects. As regards NW. Iceland, N. Iceland and the northernmost part of the coast of E. Iceland I rely on the measurements carried out during the year 1904 on board the Danish Deep Sea Exploration ship “Thor” (Niel- sen, 52).
East Iceland just south of Langanes.
. 66° 09/ N. lat. 24S: en se 14° 26’ W. long.
178 m. Depth (m.) Temp. (C°) Salinity °/oo 0 0.63 34.70 25 0.74 34.72 50 0.73 34.72 100 0.71 34.72 66° 10’ N. lat. 66° 16/ N. lat. Aug. ibe St. 2S) 44° 99/ W. long. Aug. 13: St. 100, 130 36/ W. long. 189 m. 284 m. Depth(m.) Temp.(C®% Salinity 9/oo Depth (m.) Temp. (C°) Salinity °/oo 0 7.60 34.43 0 8.57 34.51 10 Lo 34.44 10 8.31 34.51 25 6.90 34.51 25 6.00 34.69 30 5.89 34.69 395 4.87 — 79 5.20 34.78 50 3.08 34.88 100 4.61 34.85 1D 3.32 34.91
North Iceland east of Eyjafjéréur.
66° 32/N. lat. _ 66° 33¢N. lat. April Dae St. 14, 17° 50: W. July 2 tt St. 74
long. > 18° 10‘ W. long. 175 m. (om: Depth (m.) Temp. (C°) = Salinity °/oo Depth (m.) Temp. (C°) = Salinity °/oo
0 1.50 34.85 0 8.40 33.91
25 1.65 34.87 10 “TAG 34.79
50 1.68 34.87 17 7.19 } (34.85
100 170 34.85 21 6.34 © —
25 5.49 34.82
50 5.06 34.87
MARINE ALGAL VEGETATION 3a
66° 14/N. lat. 914/N. lat. aie: St. 73, 500 59. ee Aug. 15. St. 104, se hy a ieee 197 m. 226 m. Depth (m.) Temp. (C°) Salinity °/oo Depth (m.) Temp. (C°) Salinity °/o0
0 10.5 31.62 0 8.60 34:27
10 GA2 oid 10 8.52 Be | 7 6.52 34.43 2 7.84 34.47 25 6.74 34.69 oD 71 34.60 50 5.95 34.76 50 5.90 34.82 75 yay, 34.88 75 5.63 34.86 100 4.84 34.96 100 5.40 34.91
North Iceland west of Eyjafjéréur.
0 4 0 4 April 23. St. 13, ae - fee Aug. 23. St. 106. a age eae 220 m. 222 m. Depth (m.) Temp. (C°) = Salinity °/oo Depth (m.) Temp. (C°) = Salinity °/oo 0 254: 34.94 0 4.50 32.18 25 2At 34.96 10 4.70 32.94 50 ZA 34.97 17) 5.65 cee 100 — 2.46 34.97 25 6.30 33.89 30 6.11 33.93 od 4.42 39.90 50 4.27 34.54 © 62.9 5.45 34.75 75 5.62 34.83 90 5.84 34.94 100 6.12 35.05
66° 31/N. lat. April 23. St. 12, 990 95. w. long.
62 m. Depth (m.) Temp. (C?) Salinity °/oo
0 1.20 34.76
40 1.05 34.81
60 1.05 34.81
66° 29/N. lat. 66° 30’ N. lat. J une De St. OL; 929 25/ W. long. : Aug. aA: St. 107, 92° 27° W. long. 62 m. 46 m. Depth (m.) Temp. (C°) Salinity °/oo Depth (m.) Temp. (C°) = Salinity °/oo
0 552 34.67 0 8.91 34.58 10 3.49 34.67 10 8.96 34.58 DAS 3.49 34.70 20 8.93 34.58 60 3.49 34.70 30 8.91 34.58
45 8.72 34.61 The Botany of Iceland. I. . 3
34 H. JONSSON
North-west Iceland.
5 66° 17’ N. lat. April Daas St. 10: 23° 14’ W. long. 125 m.
Depth (m.) Temp. (C°) — Salinity °/oo 0 1.42 34.69 50 2.82 34.99 120 2.94 35.05
66° 20’ N. lat. June 2. St. 52; 23° 31/ W. long.
142 m. Depth(m.) Temp.(C®) Salinity °/oo
0 4.25 34.92
10 4,24 34.92
25 4.17 34.98
50 4.19 34.99
75 4.25 34.99 100 4.34 39.01
: 66° 33’ N. lat. April Doe Stil? 239 37 W. long.
84 m. Depth(m.) Temp.(C°) Salinity °/oo Os 2.40 34.97 82 2.97 =
66° 19’N. lat. Aug. 24. St. 108, 93° 27°‘ W. long.
115 m. Depth (m.) Temp.(C°®) Salinity °/oo 0 9.42 34.67 10 9.52 34.66 295 9.46 34.66 30 9.39 = 50 8.16 34.85 _ 79 1.30 34.91 110 6.76 35.01
Almost at the boundary between NW. Iceland and SW. Iceland.
65° 32" N dat June 26. St. 61, 940 34. w. long.
41 m. Depth (m.) Temp. (C°) Salinity °/oo 0 8.17 34.13 5 7.93 34.25 10 MATOS 34.34 20 7.66 34.90 40 7.61 34.52
65° 29’ N. lat. Au = ZirS 109, 940 375 W. long.
43 m. Depth(m.) Temp. (C®) Salinity °/oo 0 10.26 34.54 10 10.20 34.54 15 10.20 34.53 25 10.21 34.54 40 10.21 34.57
The measurements recorded show distinctly the range of the
temperature in April and August, 1904. By taking successively the stations 11 (April 23rd), 13 (April 23rd), 14 (April 23rd) and 15 (April 24th) it is distinctly seen how the temperature of the surface- water of the ocean along the north coast of Iceland decreases from west to east, as shown by the following figures: —-
St. 11 St. 13 st.14 St. 15 2.40° 2.34° 17500 0.63 °
A similar decrease of warmth from west to east, but in a far lesser degree, appears to occur in the month of August. : Station 106 (Aug. 23rd) shows a much lower temperature than
MARINE ALGAL VEGETATION 30
was to be expected, which is unquestionably due to the water from the East Greenland polar current, as the ice was still, or had re- cently been, in the neighbourhood.
South Iceland. From the ocean south of Iceland there are also measurements to hand carried out on board the “Thor” (Nielsen, 53).
South coast west of Dyrhé6laey.
63° 32’ N. lat. ; 63° 08/ N. lat. 106 m. 662 m. Depth (m.) Temp. (C°) Salinity °/oo Depth (m.) Temp. (C°) Salinity °/oo 0 10.89 35:14 0 10.44 35.16 Zo 9.77 35.14 25 10.18 35.16 50 8.06 35:14 50 8.07 35.16 104 7.85 35.16 100 1:67, 35.19
63° 16/N. lat.
63° 25/N. lat. ee et 2 19917 Wolong, OS OF St E14, 1904 55003/W- long.
765 m. 150 m.
Depth (m.) Temp. (C°) — Salinity °/oo Depth (m.) Temp. (C°) = Salinity °/oo 0 11.45 35.03 0 11.70 34.49 25 10.09 39.14 10 11.70 34.51 50 8.14 3) eral! 20 11.55 34.65 100 era a0.20 30 1i3od 34.92 40 1135) 35.03 45 10.95 30.07 50 9.78 35.04 79 7.97 39.22 100 114 JDO
South coast east of Dyrhdlaey.
63° 51° N. lat. May 23. St. 46, 1905, 460 95. w. long.
60 m. Depth (m.] Temp. (C°) Salinity °/oo 0 7.91 34.81 10 7.14 34.99 25 6.87 35.14 58 6.90 35.16
There are moreover some notes, given by Knudsen (44), on the temperature and salinity of the surface-water of the ocean south of Iceland. They are based upon the measurements carried out on
3*
26 H. JONSSON
board the mail steamer “Laura” on its route from Scotland to Ice- land during the years 1897—1904.
Between longitude 17° and 18°, near the coast of Iceland, in a south-easterly direction from Dyrhdlaey, the mean temperature of the year (1897—1904) is stated (44) to be 8.8° and the mean salinity during the same period 35.19.
The main features regarding the temperature of the ocean around Iceland then are as follows — At the south coast warm, pure Atlantic water of a high (above 35 °/oo) and somewhat varying salinity occurs; at SW. Iceland there is a somewhat. similar sea; at NW. Iceland and N. Iceland there is Atlantic water mixed with cold water of low salinity from the East Greenland polar current; and lastly, at E. Iceland Arctic water occurs (with a temperature of 0° to 2° and salinity from 34.6 per cent. to 34.9 per cent. [Helland-Han- sen and Nansen, 27, p. 287]): the East Iceland polar current mixed with water from the Atlantic current.
The change of temperature in the surface-layers of the water, the cooling process during winter and the heating process during summer, reaches down almost as deep as the algal vegetation, and is consequently of no slight importance to the latter.
b. The Temperature in the Fjords. Respecting the tempe- rature of the surface-water of the ocean throughout the year infor- mation is given in the “Meteorologisk Aarbog” (Meteorological Year- book) regarding three stations in Iceland: Papey, Grimsey and Styk- kishélmur. The following figures show the seasons’ mean tempera- ture of the ocean for a period of five years (1902 —1906), chosen arbitrarily. Grimsey is omitted, however, as the observations there have often been incomplete.
Winter Spring Summer Autumn Papey (E.Iceland) ..... . 0.9° 1.79 6.0° 4.39 Stykkishélmur (SW. Iceland). 0.4° 1.8.8 9.6° 6.4° Vestmannaeyjar? (S.Iceland). 4.1° 621% 10.4° 708
The winter in Papey is warmer than in Stykkishélmur, and the monthly mean temperatures during the winter, of the period mentioned, are there all positive; while in Stykkishélmur, February (— 0.8) and March (-— 0.2) have negative numbers. The summer is much warmer
* The figures for the Vestmannaeyjar constitute the mean of the period from July 1st, 1877 to Dec. 31st, 1906. According to borvaldur Thoroddsen, Lysing Islands, 2. Bd., pp. 350—351, Kaupmannah6fn 1910.
MARINE ALGAL VEGETATION a
in Stykkishélmur. A comparison of these two places is, however, not equivalent to a comparison between E. Iceland and SW. Iceland, the situation of the stations being quite different. Papey is an island lying isolated in the ocean; Stykkishélmur, on the other hand, is a good example of the thermal conditions existing in the calm fjords.
Regarding the temperature at various depths in the interior of the fjords some observations are to hand made during the summer. These are, however, too few and scattered to be given in mean values. I give, therefore, as an example, some actual measurements from different parts of the coast of Iceland.
In East Iceland the measurements of temperature were car- ried out on board the Survey vessel “Diana” (Fisheries’ Report (“‘Fiskeri-Beretning’’) for the financial year 1899—1900), and of these the following are given: —
Depthinfathoms Temp. (C?)
RfellistjorOur (9/5). 4. ...5. ees « us 0 1% 10 1.6 Laémundarfjorour ("/6).......... 0 5.0 7 | cir. 33 1.5
iactcleat |OPOUE)(2°/ 6)... 22 da cia wens 0 8.0 ih 2.5
BooMeMOROUE (29/6) 2.0 0. - + sss | 0 4.5 131/2 1.8
fommasorour (146)... mes bi als esac 0 3.8 81/2 2.4
RaMAVOMOUT (C°/7) . aa... ou ee 0 6.5 5 6.3
Bretodalsyik (o/s). sc). 4.75 bk nek 0 4.6 Bottom 4.3
The low bottom-temperature in June is probably due to the East Iceland polar current.
In addition to these Semundsson!? has published the fol- lowing measurements of the temperature and salinity of the surface of the fjords in East Iceland.
Temp. of the Salinity
surface (C°) °/o0 Diupivogur (°/s) ..... 9.0 29.47 high-water. a ae ee 7.4 33.14 low-water. Faskridsfjordur (19/s).. 10.0 33.67 | at Buoir. —- ee 9.5 32.23 at Mjdeyri. — re 9.4 33.54 at Brimnes. a oe 9.0 32°19 erat Hotton: - Crla).. 7.0 ' 34.71 at Kolfreyjusstadur.
1 Bjarni Semundsson, Fiskirannsdknir, 1898, Andvari, XXIV arg.
38 H. JONSSON
Temp. of the Salinity
surface (C°) °/o0 Vattarnes (71/s)....... 8.5 34.58 near land. Eskilj@nour 2/8) e 9.3 1.31 in the fjord, after rain. — ais) wee wee 5.0 6.73 near land, outflowing current. os ET: See ad 5.0 23.71 out in the fjord, in outflowing current. ; ~~ SO a aa 5.0 34.45 out in the fjord, in inflowing current. Norofjoréur (27/3) ..... 7.5 34.45 near land. Mjoifjordur (°9/s) ..... 6.5 33.00 at Brekka. Seydisfjérour (“/s) .... 9.5 9.23 head of the fjord. - (Aire 7.5 22.01 = — ana te 8.0 22.01 out in the fjord. — ase A Ce oe 8.5 25.04 —— = ae ee 7.8 S005" — — Sy A 7.5 31.96 —- = (Ue) cw 7.0 34.45 at Skdlanes. — (iio)! steam 7.0 34.45 at Brimnes. — (3/9) mea 6.5 33.01 at Dvergasteinn. Borgarfjordur (4/9) .... The 34.45 out in the fjord. Vopnafjéréur (°/9) .... 7.5 33.27 near land.
From the most westerly part of the north coast and from the northern part of the north-west coast as also from Breidifj6rdur measurements are to hand of the temperature and salinity of the ocean at various depths in the interior of the fjords taken by Bjarni Semundsson (Fiskirannsoknir, 1908, Andvari, XXXIV arg.) of which the following are given: —
Depth Temp. Salinity North coast, in metres ce °/oo SicingrimsfjorouriGt/7)). (be. seen mee 0 10.8 274 15 9.7 30 9.2 34.3 595 3.2 a40 SteingrimsfjoroummG/e)aa- ie tee 0 10.6 34.0 15 9.9 a0 7.8 34.6 70 5.8 34.7 100 4.2 34.7 Hritatjorour (1/3). ee eee 0 7.5 34.6 15 6.0 30 4.8 34.7 44 4.5 35.0 North-west coast, Mjoifjorour, the inner part (°/7)...... 0 11.8 30.6 25 6.5 — (34.5 50 5 34.9
MARINE ALGAL VEGETATION
Depth : in metres Sk6tufjoréur, the inner’ part (16/7)..... 0 15 35 70 . 105 Isafjardardjip, 11/2 mile NW. of Ogur- rie. (72/5) (aS aioe oe comes 0 18) S15 70 100 South-west coast, Skardsst66 in Breidifjérdur (13/s) ...... 0 (outside) 8 oA TUSSUCC) ee 0 (near land) 6
Salinity °/o0
30.5
34.3 34.7 34.7
o2.2
34.0 34.9 35.9
34.0 34.5 24.8 34.3
39
Bjarni Semundsson has kindly given me the permission, moreover, to make use of his hitherto unpublished measurements of the temperature of the ocean at SW. Iceland (Breidifjé6rédur and Faxafléi), in the interior of the fjords, from the summer of 1909.
Of these the following are given: —
Depth
Breidifjordur Stykkishélmur (the port °/7):........ 0 About 1/2 a mile SE. of Vadstakksey (7/7) 0
About 4/2 a mile SE. of Hrappsey (2°/7) 0 Kolgrafarfjéréur, the interior (27/7) .... 0
Kolgrafarfj6rdur, the mouth (18/7) ..... 0
Hvammsfjérdur about 2 miles SE. of ibambey 00/7) 6. 3... - i: es oO 0
in metres
Temp.
Cc? 10.6 10.1 10.1 Gal 10.0 11.5 10.8 10.7 10.5
Salinity °/o9 oo.1 34.2
34.6 30.1 33.9
34.0 34.2 33.9
34.2 34.1 34.7 34.8
32.7
Jo. 34.1
40 H. JONSSON
Depth Temp. Salinity ESreariten in metres aga ok °/o0 5 miles SW. of Akranes (26/7) 0 115 34.4 15 10.6 30 9.2 34.7 60 7.8 34.9 Knanarnes.c.. St ok ite. sae AE 0 14.0 34.0 About 2 miles SE. of Por- moossker (@!/7)eh . 2. sahes 0 12:2 34.6 15 10.2 30 9.5 34.6 45 9.1 34.7 Borgarnes((/s) it. 2. aoe 0 12.4 26.9 high-water. = (Ciig)s'c eee eae 0 12.4 18.9 low-water. With Seleyriu itis”. ste 0 11.2 8.8 . 5 10.6 14.7 Borgarfjéréur, the mouth (7/s) 0 11.7 28.9 10 11.6 20 eS 34.4 Hvalfjérdur, Hvammsdjup (ois amet ae eae eek 0 11.6 33.4 15 11:4 30 Tee 34.0 60 ip te 04.2 Hvalfjordur, Galtarvikurdjup 0 147 33.9 5) ss 30 i 0 ie 34.0 50 it BGI 34.4 85 11.0 34.3
From the measurements given above it will be seen that the temperature of the water in the interior of the small fjords is nearly the same from surface to bottom, while a regular decrease of warmth is immediately felt with the increase of depth in the more open waters. The temperature of the fjord-water is evidently dependent on the climate of the country; but regarding the temperature, during winter, for instance, we know nothing. Nor am I prepared to treat of the distribution of warmth in the coastal water in a more exact manner, as from the scattered observations made during the summer, which are at our disposal, no satisfactory results can be arrived at regarding the thermal conditions in which the algal vegetation exists all the year round.
C. The Salinity.
The degree of salinity is given above, together with the tem- perature.
MARINE ALGAL VEGETATION Al
a. The Sea. South of Iceland the salinity varies but slightly, with the exception of the coastal water itself. During the summer, at any rate, the salinity of the coastal water must be considerably lower on account of the great amount of fresh water brought down by all the rivers of the south. On the other coasts and especially those of N. and E. Iceland the salinity varies according to whether the layers of water originate from currents which are deficient in salt or from the Irminger current, and also with the amount of fresh water streaming out from land. At station 106 (see above) the inferior salinity is evidently due to cold water from the Greenland current, and at station 73 it is probably due to fresh water.
b. The Fjords. The salinity inside the fjords varies consider- ably and the variation is dependent upon the amount of fresh water which intermingles with the water in the fjord, partly in the form of river water and partly in the form of precipitated moisture. The lowest salinity in the fjords was 1.31 °/oo in Eskifjéréur after rain. Heavy rainfalls must be capable of causing such an inferior salinity in other places also, especially in narrow fjords, but this will not last long, and as the littoral alge can endure heavy showers during -low-tide, they will not suffer to any extent worth mentioning.
In places where the salinity is as low as in Seydisfjérdur (9.23 °/oo), where a rather large river disembogues, the algal vegeta- - tion occurs sparingly, although alge are found, especially green and brown algz. At a place like Borgarnes, where the salinity is low (18.9; 26.9) on account of fresh water from Hvita, the algal vegeta- tion occurs more abundantly than at the very head of Seydisfjéréur. by the river, but the inferior salinity excludes certain species, for instance, Polysiphonia fastigiata, although Ascophyllum occurs abun- dantly. Further out, where the sea is more saline, it is not absent.
It is especially in the surface-water of the fjords that the sali- nity varies so much. It is greater in the large open fjords, such as Faxafléi, than in the small land-locked fjords, such as Hvalfjérdéur, a circumstance which must certainly be due to river-water. The figures given show also that the salinity of the surface-water of the smaller fjords is less in the inner part than in the outer part. The same difference seems to appear also between the deeper layers of water of the inner and outer parts.
As a rule, the salinity of the deeper layers is higher and more stable, which must be beneficial to the vegetation in the depths.
42 H. JONSSON
ah PBCATR:
The climate is of special importance to that part of the algal vegetation which is exposed during low-tide. The temperature is possibly of least importance in a climate where high and very low degrees of temperature do not occur, or are, at any rate, rare. The degree of humidity of the air and the cloud-covering are, on the other hand, highly important to the algal vegetation which is left dry. The movements of the air are also of importance, especially as it produces movements in the sea.
A. The Temperature.
The following means (19 years)! from a number of stations on different parts of the coast are here given for the elucidation of the thermal conditions.
E. Iceland Winter Spring Summer Autumn The year Papey ot eee: AG Ge eae 0.1 6.0 5) 2.1 BenuijGrOumy .ayiee epee clio. Beene —1.4 0.8 7.6 3.9 2.6 N. Iceland PVA AH OLE ae ids Oe ee keene —40 —19 6.5 1.6 0.5 GTTMSEY* o-oo Bete ete es Sa esis ee ba 6.1 2.9 1.3 SW. Iceland StykkiSholmpr ce shccks ogres ately. eee 0.8 8.9 3.9 2.9 S. Iceland : Vestmannaeyian gti <9. os ora at 3.8 37 5.2 5.0 my rarbalkka (ei Perccate st etactre. S711) Ze 10.2 3.5 3.9
From the figures given above it will be possible to form an opinion of the thermal conditions in the places mentioned, and these are altogether such that an algal vegetation left dry can thrive everywhere along the coast. The extremes will not have a sufficiently injurious effect on the vegetation for it to be noticeable in the long run. High degrees of temperature, about 20°C for example, occur rarely in the summer, and will have no permanent effect. Very low degrees of temperature in the winter will not injure the vegetation left dry to any extent worth mentioning, as it is then partly pro- tected by snow (at the very top) and partly by ice.
I do not consider the cold in the winter injurious to the vege- tation which is left dry, as the algz certainly endure being frozen fairly well. At least I have seen uppermost in the littoral zone,
* Willaume-Jantzen, Meteorologiske Middeltal og Extremer for Fzeréerne, Island og Grénland, Kj6benhavn, 1899.
MARINE ALGAL VEGETATION 43
early in May, algz which had been frozen hard during the night, apparently quite unharmed and alive when thawed, nor could one perceive next day that they had suffered at all; but, as I was tra- velling, I was not able to observe them more than these two days. It is also a foregone conclusion that the alge left dry must freeze in the winter when the cold is severe, but it does not appear that they suffer thereby.
If the cold cannot be said to have any directly injurious effect, yet indirectly it may hurt the vegetation (though not to any great extent) by the fact that the water freezes and the beach becomes ice-covered. During severe winters a covering of ice may be found during the greater part of the winter in the smaller fjords, and especially where the fjord-water is abundantly mixed with fresh water, and even if the winters are quite mild, yet from time to time the water next the beach may freeze. In the littoral zone and on rocks which are laid bare during low-tide, the ice forms in ac- cordance with the substratum, and if this is uneven the ice breaks. At high-water the ice-covering is lifted up; the pieces of ice may then freeze together again, and break once more with the next ebb- tide. During spring-tides in particular these movements are rather considerable and the plant-covering may be a good deal damaged thereby: but if one regards the coasts in their entirety these distur- bances will prove to be of small importance.
The drift-ice is much more dangerous to the algal vegetation as the icebergs scrape the rocks with which they come in contact. Stromfelt, when travelling in Iceland in 1883, the year following one of the years notable on account of the great quantity of ice, found the littoral vegetation poorly developed in the north country. This most certainly resulted from the drift-ice having blockaded the coast during the whole summer of 1882. In the summer of 1898, I saw on the promontory between Seydisfj6réur and Lodmundarfjéréur distinct signs of the drift-ice which had been there in the spring. The injurious influence of the drift-ice consists mainly in the fact that it scrapes away the vegetation from the parts with which it comes in contact; possibly also in the fact that it reduces the tem- perature to far below normal. That the plants suddenly find them- selves in a much colder medium than they are accustomed to must produce a check upon them, particularly on the more sensitive species. The marine plants, however, are less affected by this than the land vegetation. As a rule, ice-years occur at fairly long intervals;
44 H. JONSSON
consequently the damage which the ice causes is not noticeable in the long run, it is noticed chiefly in the same year or-the year following, and is remedied comparatively quickly.
B. The Humidity.
Very great importance must be ascribed to this as regards the algal vegetation left exposed. During the period of desiccation there is always the danger of the evaporation becoming too great, espe- cially if the air is dry. The more humid the air, the better the algee will be able to maintain life in it. The following figures from four places, each situated on a different part of the coast, show the mean humidity of the air as percentages (Willaume-Jantzen len)
. Winter Spring Summer Autumn E. Icel, Berufjordur @3 years): 20.4... 77 78 81 80 N= icel. (Grimsey . (2a veGars) c's 8. en eeee 83 83 85 86 SW. Icel. Stykkishélmur (20-23 years) . 88 85 83 86 S. Icel. Vestmannaeyjar (12 years) .... 81 79 82 81
As a comparison with the Ferédes might be of interest, the figures showing the mean humidity as percentages at Thorshavn Willaume-Jantzen, |.c.) are appended.
Winter Spring Summer Autumn
Thorshavn in the Fer6es (25 years).. 81 79 84 84
From these figures it appears that the humidity of the air in Berufjérdur is less than in the Ferées while the humidity of the air at Grimsey and also at Stykkishédlmur is greater than in the Feerdes. The humidity of the air in the winter and the spring in the Vestmannaeyjar and in the Ferdées is the same, while at the latter place it is a little greater in the summer and autumn.
C. Precipitation, Amount of Cloud, Foggy days, Wet days.
a. Precipitation. The following figures show for purposes of comparison the mean downfall in millimetres at four places in Iceland, one on each coast, and at Thorshavn in the Ferées (Wil- laume-Jantzen, 1. c).
Winter Spring Summer Autumn The year E, Icel.. Berufjérdur (23, years)... 348.0. | 222.7 | 203.7. 34035 eae N. Icel. Grimsey (16-22 years)... 83.5 64.8 85.6 139.9 373.8 SW. Icel. Stykkish6lmur (18-22 yrs.) 191.5 115.2 113.6 203.8 624.1 S.Icel. Vestmannaeyjar(15 years).. 354.1 257.3 2521 402.2 1265.7 Thorshavn in the Ferées (25 yrs.). 510.9 485.2 272.4 3246 1593.1
MARINE ALGAL VEGETATION 45
As shown by the figures there is a considerable difference in the amount of precipitated moisture. That of Thorshavn is greatest, next come the Vestmannaeyjar, followed by Berufjéréur. The preci- pitation at Stykkishélmur is not more than half that in the Vest- mannaeyjar, and that of Grimsey is not more than a fourth part of that in the Vestmannaeyjar.
b. Mean Amount of Cloud (Willaume-Jantzen, 1. c). Scale 0—10.
Winter Spring Summer Autumn E. Icel. Berufj6rdur (23 years).:...... 6.4 6.6 6.9 6.6 Nelieel Grimsey, (22 years).....1..... 8.5 8.2 7.9 8.5 SW. Icel. Stykkishélmur (22 years).... 7.1 6.4 6.0 6.9 S. Icel. Vestmannaeyjar (18 years)..... 6.2 6.1 6.1 6.3 Thorshavn in the Fer6ées (25 years).. 7.4 Ppa via 7.9
The amount of cloud is greatest in Grimsey, and there is no great difference between the remaining three coast-stations in Ice- land. In Thorshayn, however, the amount of cloud is considerably greater and consequently this place approximates to Grimsey.
c. Foggy and Wet days. Mean number of Foggy days (Wil- laume-Jantzen, |. c.).
Winter Spring Summer Autumn The year E. Icel. Berufjérdur (23 years). 44.0 52.0 67.0 49.0 212 N.Icel. Grimsey (22 years)... 2.4 13.0 31.0 7.0 53 SW.Icel.Stykkish6lmur(22 years) 1.0 2.6 4.1 13 9 S.lcel. Vestmannaeyjar (18 years) 7.0 12.0 21.0 12.0 De ThorshavnintheFeroes(25yrs.) 3.0 10.0 29.0 9.0 SM!
The number of foggy days in Berufjéréur is remarkably high, and at Stykkishélmur is extremely low. In Grimsey the number is much lower during the winter months, and higher during the summer months than it is in the Vestmannaeyjar; there are also small differences during spring and autumn. There are only small differences between the Fzerées and the Vestmannaeyjar, except in the winter, when the Vestmannaeyjar have twice as many foggy days.
Mean number of Wet days (Willaume-Jantzen, l. c.).
Winter Spring Summer Autumn The year E. Icel. Berufjérour (23 years). 52 43 34 48 177 N. Icel. Grimsey (22 years)... 40 29 29 45 143 SW.Icel.Stykkishélmur(22 years) 958 47 40 52 197 S.Icel. Vestmannaeyjar(18 years) 64 595 47 59 225 Thorshavn inthe Feroes(25yrs.) 81 66 58 74 279
At all seasons the number of wet days is highest in the Fzrées
46 H. JONSSON
and in the Vestmannaeyjar, yet considerably higher in the former place. Grimsey has the fewest wet days, and Berufjéréur and Styk- kisholmur have somewhat similar numbers.
It is in the spring and the summer especially that the desicca- tion, during the period of exposure, may have an injurious effect in the zone laid bare along the coast. The amount of cloud is of course important, since clouds diminish the ‘danger of desiccation, but the mean figures are not sufficiently elucidatory. Bright sunny days are not propitious to the vegetation left exposed, especially if several such days occur in succession; and if this takes place at neap-tide, the vegetation which is found above Pelvetia-Fucus spiralis is in danger. Although the weather in Iceland varies greatly, longer periods which are damp or dry often occur. Clear days are not uncommon in the spring and summer, and. periods of even a week or more of bright weather are not rare. On bright sunny days in summer the temperature may rise rather high; I have measured 20° C. on such a day in a pool in the littoral zone, in the plant- covering itself, and the temperature of the air may rise even higher.
The periods of bright and dry weather are certainly of impor- tance as regards the upper limit of growth of the algal vegetation during the summer. The Ferées are probably less favoured by clear weather than Iceland, and the difference in the upper limit of growth of the algal vegetation in Iceland and in the Ferées may possibly be partly explained by this.
D. Winds.
The following figures show the annual percentage (Willaume- Jantzen, l.c.) of the winds: —
Berufjordur Grimsey Stykkisholmur Vestmannaeyjar IN aii Re Rca hance teeeveee 6 8 5) 13 NE th aS cae 24 18 18 2 | RNA A ra Se fa RE + 20 20 23 SIE B8o0o ye adenine v5, cee 6 16 16 9 Ro ENS Ia Sa ARM Ff 8 4 ii 8 SW ASME Si crn bhebe eer sheng 15 5 10 10 WW SENSE ie nceuaue aust cee ooh + 2 7 8 IN WV cicero aca eects a 23 7 3 + Gali 22% Se Bt aye facets: 10 10 12 22
MARINE ALGAL VEGETATION 47
It happens rather frequently that the winds are stormy and, as an example, the annual percentage of storms for Stykkishélmur (from */9 1845 to *4/2 1892) may be given: — N. 32, NE. 61, E. 13, SE. 17, S.44, SW. 31, W. 26, NW. 11.
The frequency of “calm” is 10 °/o at Grimsey and in Berufjéréur and the frequency of “wind” is therefore .90 °/o in both places; at Stykkisholmur the frequency of “calm” is 12 °/o and that of “wind” 88 °/o; in the Vestmannaeyjar the frequency of “calm” is 22°/o and that of “wind” 78 °/o.
At Thorshavn, in the Ferées, the annual “calm” is 11 °/o and the frequency of “wind” 89 °/o, somewhat the same, therefore, as at Stykkishélmur and greater than in the Vestmannaeyjar.
4. LIGHT.
The influence of light on the distribution of the algal associa- tions and on their appearance is, as is well-known, exceedingly great. Without doubt most investigators assume that the main di- vision of algal vegetation into a green, a brown and a red zone is due to the quality of the light, but one cannot on that account consider the intensity of the light to be of no importance. To what extent the shades of colour in the red alge are to be regarded as an adaptation to the intensity of the light or to the quality of the light, I find rather difficult to decide.
I agree with Berthold and Oltmanns in thinking that the Floridee may be characterized as shade-plants in the same sense that we speak of shade-vegetation in lava-clefts and in other places where there is a faint light. By shade-plants I understand plants which prefer feebly illuminated spots, and do not, as a rule, thrive in the full light of day. In the tidal region (Part VI) the littoral Floridee evidently prefer crevices and grottoes, i. e. feebly illuminated places, and thus prove themselves to be shade-plants.
I shall not enter more fully into the question of light, as I have made no experiments in that connection and, moreover, the subject requires to be reinvestigated (Oltmanns, 54).
Il. THE HORIZONTAL DISTRIBUTION OF THE SPECIES AND THE COMPONENTS OF THE ALGAL FLORA.
| the following list (Table I) of the hitherto known Marine Algee of Iceland a letter (A, B,, B,, C, D, E,, E,) is placed before each species, showing to which plant-geographical group I refer it (cf. B6rgesen and Jénsson, 14). A indicates the arctic group, B, sub-division 1 of the subarctic group, B, sub-division 2 of the subarctic group, C the boreal-arctic group, D the cold-boreal group and E the warm-boreal group. The letter c placed after the name of the species indicates that it has been found in all the five coastal districts (E. Icel., N. Icel., NW. Icel., SW. Icel. and S. Icel., see above, p. 5); a (c) placed after the name of the species indi- cates that it probably occurs in all parts of the coast.
Table 1. The Distribution of the Species along the coast.
E. Icel. | N. Icel. |NW.Icel.|SW.Icel.| S. Icel. Rhodophycez. |
C Bangia fusco-purpurea (c) ........... + ak a = “bh C Porphiyra, ambilicalas"ey,o. 60. ee + + + a a B, Pvininiatatic 208 Sok RR. ee heer ae + + + + == D Porphyropsis¢occimead .rsit 4) diet. . oe Bs a 4 +- 188 Conchacelis rosea. 682500 Ms ose | + oa a a ok C Chantransia microscopica (c)......... + ye i D C. Alarize Gamer ee. fore cam ee ee ee as 4: a ak C Esecunidataehege we se) Aa, MRS a + > + + B, G. wingatulas(@) geseiaons Lier Weta’: eee + + my Ee. Chondrus .crispusie fe: eee ee eo is +) + + D Gigartina’ mamillosa (6) 2: (224.5020 + le i? + _ Cc Abnfeltia: plicata (Wet se eee Ne tH) bi + ab B, Phyllophora Brodizi * interrupta.... | —+ ts ab ae Res D P; membranifolia.<: ee ee | Ee ob _ B, Actinococcus subcutaneus ........... a _ 73 ty A Ceéeratocolax, Hartzii 2a ee | os zi
D Cystoclonium purpurascens.......... + | ak + +
Table 1.
H. JONSSON: MARINE ALGAL VEGETATION
e - to to
tw
—
we
Lom i~)
to
pr
H rm
-
ol les tesla > oh iles| Lelie coll loli utes oll lelslo| te) tell} 12)
DWUOMODWDOrPOoOM ee nroraroawrnwre
MienerellamPeMmnyl:... cece tose 5d. 442 PAMOnA ETIStata Co 2 0.05. 2 SP Seed ede Rhodophyllis dichotoma (c).......... Muodymenta palmata’c.....:...05. > omentaria -clavellosa:.....2:02.. 5.2:
WeBaerw ~ corymbosa ..... 222.0. sss PESOS yh sys 1. Sas hs Sale se S58 RN Ws aIOUINed sy. a). Heh Lk Se Nk Pe: Bonnemaisonia asparagoides.......... Eteresiphonia parasitica’... . 2.2... Eolysrphonia ureeolata ¢.... 20.26.26: 2 TRIS OTE ee ne ae ee eae 121, Qu GUU OE gs IN oie eye Cee ee nea Pee SECINS! Mets Site uss ie RS a ada oe Rhodomela lycopodioides c.......... Wdentwalia dentata Ch. 20i.66 6.6.2.6. Callithamnions Arbuseula.... 2.021... 5. PSCOPMMOnUIMIEN. fei. 5 . ws ayo Daisies © Aisha PMI APAMELEBATIS © (2/55 60. ve spose > Sos Renocwrplimosa 25 oho als se lew ee Se CCUM ALA tie ee 2 2 cos agehs, Mags Steers SS Antithamnion Plumula v. boreale (c). NSTI OYGRO SUS 0 Ig (Sp a a er ae Ceramium acanthonotum..........
PEPESHONPCMAMIPL 00%. 055 2 = + ales eyes PEGINICMMOSUMMN chi. oss. wp. se see Oe POUL CORO AIIM. oa) «occ. occ Steins ¢ PApOR SECIS eric to 8c, 2 sees Geta PAPIMUMUVCTIINE 2. aor stom) Sis. ticle ete tees SOLO OTT aN CE), Some et cane nee oe ee Rhodochorton Rothii c... RRS UCM S cate Reta gal vonis «ene + viowere et Sue MIDI EN ATE) Ce OA re ec ea Ee PeMIc forme (6) <.\...2 ema wok os R.amentbranaceam (¢) 0.7 Wen ih.ee. Piamorntiafrliformis “(C) hod <s. cne a oy WEISCAMEONIIS es. 9) a shete ees Shs hes Petrocels (HeEMned yin... So as eee Cruotiay Arete! «0528 cs ths war ered eee Berge Mbit s Stee a ole: aghats saw iaiey ettve ss Peyssonellia HOsenvingil 65/20... 0.
Diglar lewplepii Lg
eve, wy er 6 Le Ve, ese Xe,
HRhododermis: parasitica’... 6. 6..c66 03 /
The Botany of Iceland. I.
49
The Distribution of the Species along the coast (continued).
| E. Icel. | N. Icel. |
NW.lIcel. SW. Icel.| S. Icel.
a + — aa
+44:
+++:
| | |
oe — — —
+:
a te te cca is a a eae a
yaa
+4:
a isig pia
++: +44:
+++
ti itt: t+:
++:
FEEEFEFHEEHS FEE HEHETHEFEEHEEHHTHEHHFHH:
a
++: +4:
++teo44+: $++4+4+44: 45
++++4++4:
tea
+444:
5 ee
+:
+: +:
50
H. JONSSON
Table 1. The Distribution of the Species along the coast (continued).
te
i i
_—
Sees ee oa - oon
_
i
tS
_
a
to m u
ele eile ieiews! terl ig le) ed ele) tes teh este) tor tes) We) desl lech be) to2
is} iS}
i
_
rWeoOooOww
Lithothamnion glaciale (c)........... Me AW gem: (Gan ected aoe Sea eee le tophiformen(G)a i ho. Went eben o ste Lc BlAVESCOM'S Ro ocho cyAe aud Meta ettnn, idee is A AOCCUINGIIT 9 Arley: Gonenero sheneanhen Sarees
Phymatolithon polymorphum ........ Clathromorphum compactum c....... Lithophyllum Crouani............... Dermatolithon macrocarpum......... Corallina officinalis suis) ane,
Phzophycee.
Lithoderma fatiscens (€)..3..2:....-. Petroderma:maculiforme: ...S.¢0: :-.. Ralisiatovatan(e): <« Sodan oie. a oars Reclavatar(G)ae ss seen aes ceed wees IVs VET OSA 716) si: tent Net bin os oe Pee RO destagG) 9 ai. tetas Sebo tneeeh a eee Myrionema vuleare. i ocon. oan ota I Oost Go) STUN Cu cae ee eet WP Seep earet eee MGs Wi SlOWOSMMAUA(G). oars. ass. de sass he Oh eee IM TET OCRSC® srtereca ioc ein nse Pools wo Ske Stop M.\Laminarizey (©) 2a .4- <b cae ine Ascocyclus ‘tslandicus:5. tn 8. Coes ae Microsyphar Polysiphoniz (c)........ Streblonema ecidioides (c)........... S: sulophorzV- cespitoSa: C.. 4 ..265 a: Pylarellaniittoralisve 2 Faten , thx te eee Ectocarpus tomentosoides c.......... COMTEMEOSUSS V2 i nic. Mae's Wee op RG
SSIMEHIOSHSACE)AS Wire seul ae tate wi ee Mpemicilatise(C)ne acc. 5 Mees eee s et oa e fascicullatus sees. Mths eee wea oe BB Wo co Fe Sine SSR reins 2, ee a Mn Uae Cas Leptonema fasciculatum v. subcylin-
Orica, (Ce) AN oc games a alt etetae cea aae Elachista fucicola¢2h e434 3.4) ose bee Sphacelaria britannica (c)............ Siradicans "(C) ins ye hen ieee ae awe ane S: olivacea .. Fos. in pees ore eae ae eee Cheetopteris plumosa (c)............. Omphalophyllum ulvaceum..........
eos eoRcoes
E. Icel. | N. Icel. |NW.Icel.|SW.Icel.| S. Icel. ogee) + +4 | +) ade ae “bi |i oob o/oa eee + |... Sl ieee oem a se +} +})+]+)4 ae at. % 2 ca “ee +) +]+)4+/+ |) ln |) 4 Lose one +|+)+)4+]+4+ +/+ ]+ ]4 =p a; |) ea +) +) +) 4 + | + oh oe +) + + 1s + + | + | +) ee + 4 Je | ae Me pes, 4 | shall +/+]+])+]4 +i) +) +)4+] 4 +} +]+)4+)4 _ x eh + | +3) oe Bl ae + + | + 4 0 + | + + ooh +) +)+)+)4 ‘cla + | + +o] cb fo-aio ee 6g . | 4 +} + )+)4 +
MARINE ALGAL VEGETATION
51
Table 1. The Distribution of the Species along the coast (continued).
rs i
i
we
pels eriel eelleleleteelNok les). lee t=) (ee!
Punctaria plantaginea (c)............ |
kitosiphon filiformis (¢) 4...........-
Isthmoplea sphzrophora (c).......... | Stictyostpbon .tortilis(c)......:...... ! Pheostroma pustulosum (c) ......... |
Scytosiphon Lomentaria c...........
Phyllitis zosterifolia (¢)......:....:.. |
BIAS CIA Cle Be hy ey oe ce ee ssi Coillodesme ‘bulligeran) ©... 05s. o ss aes os Dictyosiphon. Ekmani.... <6.) .. 4+ ce... BPEMVESOCLOVA Sothern eo asics os ce se ee
Wathnordatia, (CO) sok. sos oe oe |
DACOnVMIDOSUS, 64! veka Sik eo we Dei PUT OLAESs (GC)! ode vc we cs aie wn ake d Dpocmienlaceus,(C). i... es ens ss MICSHINARESUIAr VITIGES! Ce. ue. aa See oc nt al DP ACMneaAba Ces Pe Sah. ts de ee ee
We lieulatas2 2.2... case Soke wah aah. secs Maks | G@astagnea: viréscems (C) oi... 2.00. + i -Leathesia difformis
* ete, (ee) 0) ey/e) fal) wp. 0 40) 4) sa) ©, ele
Chordaria flagelliformis c
eee es ee eo we ew ww
Ghordas tomentosa’ (G).. 0.0.20. 25%. |
CC) PDI ((O) 2 ee eee) a Saccorrhiza dermatodea (c) .......... PamimartaSaceharina Ci. .66 ue eee MEPIEELOCIISIS tee Saya ade Phin ey ae we 8 Ue TUTTO OSS ee ch eae Ra | 55, GIENICTIG SG ecg oP eo EME ICE DOUCA, (6. fA che 5% ass0ye wiahtyeeeee in
PM MRA be RALU RG ee ite a o%e aye «ne eres 0%
PVPCSCUNGMEANC A, rk vi bic) ats .o sce es lene ee otis RUCUS PS pIrAlisn(G) ike. ho. Se eee STE ISOC ee ee EE
Chlorophycee.
Chlorochytrium Cohnii (¢).’.).....-... Germelusiiaa (6). 2 vig Ge os ey ese ees ee Fs ca dermatecolax (6)iid.i Gig. Wels a aie o's Ge Senate CE). 5 .5s-eeiesls So aelated wes Codioham. Petrocelidis: 20.0.5 wsh.. ss.» CPs G SARC (CC) oe s-asm se ses oars 0s ose
| | E. Icel.
+2: +4+4+4+4+4+4+4+
+++:
+:
fod: $t+4+tt++tt+stt+:
Gmomstilum (GC). eee cote ee cc es 8
N. Icel. |NW.Icel.|SW.Icel.| S. Icel. +} +]. Se 2 + + {+4 CVG he oe ae +/4+)+]4 a + + 4 4
+) + a + ste 3 st - Slips ete UI 2g + +/+ > 4 + +/+. + + > 4+ + +) +f) +] + - oy. (oa + + 2 eae rete Se +/+ ])4+)]+ +. + + + 4 + +) 4... + +) +4 4 _ + +) +) +4 + + + 4 +) + 4+ 54 + +) + 4 spi hacmaniaee 1a +) +) 4+ 4+ pat ar aa ae +) +] +i+ Bia | abe 0 +) +) 4+ 4+ re sy + +} + | 4+ 4 + + +- + 4*
52 H. JONSSON
Table 1. The Distribution of the Species along the coast (continued).
E. Icel. | N. Icel. |NW.Icel.|SW.Icel.| S. Icel. B, Percursatia,, percursa (¢) see ea Abe a. D Enteromorpha aureola.)j9 ae + we = De oR cimizaeee ee ee Ec, | eee eee EBD i y: Mk + = C BE imtestimalis. c 472.96.) othe eer + a + — + C EY clathir altar) (Cy ies, teak octane eer + + ne -. = A Monostroma groenlandicum.......... + - 4. se big B, MES Grevallei ens ©) ra alice eae -- + + + + B, Mipuind ulate ete er nt one. ovate + + a. + + B, NES PUSCW INC ee ee eo orn Ae +- + aL ~ + C Wiva slactuica’ (G) yn cers. wee ae +- + a + D Prasiola? polyrthizai(e).. 4. thet eer a fs + + D Pp; furiiracean (oe. 7s 8. eee a era ee: a + + Me) D Pistipibata’.(e) Mc. ny oe ee ete ae - | + + + + B, Ulothrix consociata v. islandica. . J + wa B, W..subilaccidat(e) im ache ante <2 av + + es ne By Wipseudoilacca (Giese are tase + Hy + + B, UAC Cach aaa Cee at eee weee | ob +) + + + B, Pseudendoclonium submarinum (c)... + ig ; D Entoderma Wittrockii (c)............ + + + Bi Acrochwte parasitica: (6) a.via0..8 ee oe Me + D A SREPEUIS Bapres 2 in, corps apes Sia Wen tvacoee aie af fs aa B; Bolbocoleon: piliferunm (G)i.2 2.2. os. i od + + os re B, Wivellattucicola (Ce 6 ae eee ok ai ve + + B Pringshermuiacscutata (C)es: 25.5 aot ae + + D Ochlochzeteferomi(G).. 0a. ft eee a, + - . B, Urosporacmailralsilis cen eoiteece sr tenes + aL, + + + B, LOAD CUS A SI (e) i wate os WA ICN NR Ss + i Nee + + Bb, Ws Worniskioldiivenen sae sO: Ae on + =: + + 5 C Chetomorpha tortuosa (c)........... +. = dig + oe B, C. Melagoniumme tao itera a.4c 2a eee ee os + + a C, Rhizoclonium riparium (c)........... +- + aa B, Spongomorpha vernalis (c)........... “ae ey Ad; + D Acrosiphonia albescens c............. -+ == + + + B, AS MCU MAC CRN. co oineiomenae an et ae + ok + + + B, A Hy Strixcn(@) in chistes aa ag — + +- —_ oe D A; flabeliittonmiste.. 3c) a eco ee ae + B, A. peniciMORMIS eR : oe en we eee + eS BY os os By Cladophorayrupestris icant ots. ha BA = + + B; | Gahintay(On eee ee ee Cann i ae B, CSericea (C) ee Ge Re ee ate + + D Cuglaticescens (0) eae ok ee eee ts & + C Gigracilis:(C) en wine. 6 eee cee + as Ke + C Gomontia polyrrhiza (c) ............. a + + + B, Ostreobium Queketti (CG). ss. + + + + |
MARINE ALGAL VEGETATION 53
Table 1. The Distribution of the Species along the coast (continued).
E. Icel. | N. Icel. [|NW.Icel.|SW.Icel.| S. Icel. Cyanophycee. . B, Pleurocapsa amethystea c............ ok aa = | + + D Electonema norvesicum (c).........- — ae fe a E Phormidium autumnale (c).......... ae owe we C Spirmlina subsalsa (c)i 202... oe eh a2 aS + C Calothrix scopulorum: (c)...2......2+ + - 1 a C SAMARIA ALAN (G)) or) a 2 ob ele ek. cle a 8 ae - be: +
From Iceland (31, 14 and 57) there are published 76 species of red alge, 67 species of brown, 51 of green and 6 af blue-green — 200 species in all. All of these, of course, are not equally common along the coast, and their habitats, as far as these are known, in the five districts into which the coast is divided, are given in the above table. That table shows that comparatively few species occur in all the coastal districts (in the table, such are indicated by the letter c placed after the name of the species). In all parts of the coast are found 15 species (20 °/o) of red algze, 18 species (26.8 °/o) of brown, 10 species (19.6 °/o) of green and 1 species (16.6 °/o) of blue-green. Thus, of the 200 species there are 44 species (22 °/o) which are common to all the coastal districts.
If we take into consideration the fact that the great stretch of coast round the whole of Iceland is as yet far from accurately investi- gated, we may expect, after future investigations, not only that several more species will be found, but also that the distribution of the species in the different parts of the coast will prove to differ from what is at present stated to be the case. Therefore, in the above list of the distribution of the species along the coast I have placed a (c) after the name of those species which, as I surmise, are pro- bably to be found in all parts of the coast. I base this supposition partly on the position of the habitats already known along the coast, and partly on the occurrence of the species in the adjacent floral districts, e. g. the Feerédes and Greenland.
The mark (c) is subjoined to 14 species of red alge, 29 species of brown, 32 species of green and to 5 species of blue-green. On adding to this the above-mentioned species which have the letter c subjoined we get 29 species (38 °/o) of red algze, 47 species (70 °/o)
of brown, 42 species (82 °/o) of green and 6 species (100 °/o) of blue- | green. Thus, of the 200 species 124 prove to be common to all parts
54 H. JONSSON
of the coast. The percentage of each group is of the greatest im- portance, and for the sake of explicitness I have arranged these figures in a tabular form, both those which refer to c and those which refer to. c + (c).
Species common to all the coastal districts, given as percentages.
Red Brown Green Blue-green All the groups algze algze algze alge collectively Ce a ae 20 27 19 17 22 C +-(€) sre 38 70 82 100 60
On considering these two series of figures it becomes evident that the figures given for c + (c) come nearer to the real facts, while those given for c merely indicate an incomplete knowledge of the coastal distribution of the species. The fact is that, where there is not a greater climatic difference between the different parts of the coast than is the case in Iceland, it may always be expected that, as regards the common species, the highest numbers will fall to the green and to the blue-green alge; and where the hydrographic differences between the different parts of the coast are as pronounced as they are in Iceland, it is natural that the smallest number will fall to the red algz, and just as naturally the brown alge will in this re- spect be placed almost midway between the red and the green alge.
Therefore, as regards the floristic difference between the different parts of the coast, particular stress is laid on the remaining 76 species. In the following table they are arranged according to their habitats. Under A, those species are given which either occur in E. or N. Iceland only, or are most common there, and thence are dis- tributed southward along the north-west coast as far as SW. Ice- land. Under B are given species which either have been found in S. or SW. Iceland only, or are most common there, and thence have a distribution northward along the north-west coast, many of them having, moreover, an eastward distribution along the north coast.
Table 2. The Distribution of the 76 species not common to all the coastal districts.
3 3\¢ a/s|3\¢ ae = i) c) iP) o i?) Vv A sf rm. | Sai oS (| Cee prea f= seal] psa wan tb sea B — — = & — — — > = — PT Ne az mz ee | el Z| a n
1. Lomentaria clavellosa 2. L. rosea 3. Plocamium coccineum
bar
1. Lithothamnion flavescens |
+
MARINE ALGAL VEGETATION 55
Table 2. The Distribution of the 76 species not common to all the coastal districts (continued).
lee
pe ap aie) eal eee ah mi gee x $| 3) 2) 2| 2/3) 2) 2) 8) 3 3 colt tc dle |e ere = | 2. Omphalophyllum ulva- | ? | 4. Bonnemaisonia aspara-
SES oy. oy ear airs ORT Paste goides 5. Pterosiphonia parasitica 6. Rhodochorton repens
3. Laminaria nigripes ..... SriSredcoe ecu eeee TMP linea eoe HOR pOIN Uae! phum 4. Acrosiphonia penicilli- 8. Myrionema Corunnze PED AA AA oo a + | 9. Ectocarpus Hinksize |. 10. Desmarestia ligulata 5. Delesseria Baerii........ ae: | 11. Acrosiphonia flabelliformis
1 | 12. Porphyropsis coccinea | 13. Chantransia Alariz
6. Turnerella Pennyi Sioa op eee + + 14. Phyllophora membrani-
folia
Ftttttt+ t+t+++++ 4444444 +44
7. Lithothamnion foecun- 15. Delesseria alata APG | 3.7. fy thr al Re . Callithamnion Arbuscula 17. C. scopulorum ae Ae 18. Plumaria elegans 8. Laminaria feroénsis. ../+ + ).. IEA a eee ta A | 20. Cruoria pellita 9. Petroderma maculiforme.,..|-+)|.. 1 21. Dermatolithon macro- 1 carpum 10. Ascocyclus islandicus .. +).. | | 22. Ectocarpus tomentosus 23. E. fasciculatus , A ; 24. Fucus serratus 11. Dictyosiphon Mesogloia.. + ).. ! 5b. Pele ctandanticulota | | 26. Enteromorpha Linza a2 DL CorymbpOsus........... + ).. | 27. Ceramium Deslongchampii 28. C. atlanticum - || 29. C. fruticul 13. Enteromorpha aureola . ae we apie Hs
30. C. circinnatum
- |31. Rhodochorton minutum
- || 32. Dilsea edulis
- | 33. Lithothamnion Lenor- mandi
34. Myrionema fzroénse
14, Ulothrix consociata v. is-| ee EVI? 0 aia ee a
+++++tt+ F+tt+ttetts++ F444444+ +44:
42. Acrochzte repens
cir 2 ae bet + 35. Dictyosiphon Ekmani Aine -- || 36. Codiolum Petrocelidis - +4) + ||37. Chondrus crispus Soe otal) Brodist:., v. 45/35 |-Hlgs\pelysiphotiia fstigiata “IME 2ST ae a lala dl + | + | 39. Rhododermis parasitica + + | 40. Sphacelaria olivacea 17. Actinococcus subcutaneus | + | .. | +- + =| 41. Cladophora rupestris a
56 H. JONSSON
Table 2. The Distribution of the 76 species not common to all the coastal districts (continued).
A al} 2|2| 2] ole lz FE] ui i 18. Ceratocolax Hartzii..... +. | +);+/+ ..|43. Ceramium arborescens | | . Dob 4+ +) 44. Ahnfeltia plicata 19. Polysiphonia arctica .... |/4+/)/+)+/+.. |. +/)+')+ | +-| 45. Cystoclonium purpura- | yee scens 20. Ptilota pectinata........ +)+)+)+)..]).:}/4+:)+|+| +146. Ptilota plumosa Ra .. +/+ > + +47. Petrocelis Hennedyi 21. Peyssonellia Rosenvingii. | + + |-+ |-+- .. +/+) + +) 48. Corallina officinalis | - +/+)... |) --) 49. Lithophylum Crouani 22. Coilodesme bulligera.... |) ..)+)+ | ..i/+)..) +) .. || 50. Polysiphonia nigrescens eye af-| 51. Myrionema vulgare 23. GEOriA, arctica nn jsvarten.s Bi 2 a a eet + ..| 52. Leathesia difformis | (+)).. + +) 53. Delesseria sanguinea Total... 15/13] 8 | 5° ..|| 1 |10|13| 40; 40] Total
To illustrate more distinctly how the species with a north- eastern distribution (A) and those with a south-western distribution (B) intermingle in N., NW. and SW. Iceland I subjoin the following figures taken from the preceding table: —
E. Icel. N. Icel. NW. Icel. SW. Icel. S. lcel. Ge) 10 13 40 40 B A 15 9+4 8 5
Notes on the species. Of the 4 species (A, 1—4, Tab. 2) which have been found only in E. Iceland, Nos.1 and 3 occurred in great abundance in several of the fjords, while Omphalophyllum was found only in Reydarfjéréur, where it occurred abundantly, and Acrosiphonia in one place only. Delesseria Baeriti, I suppose (31, p. 140), has originated from either E. or N. Iceland.
Turnerella is most common in E. Iceland, and in addition to the habitat in N. Iceland which has been published (31, p. 135) has been found by B. Semundsson in Steingrimsfjéréur in the most western part of the north coast; consequently it must have a wide distribution along this coast. With regard to Lithothamnion foecun- dum and Laminaria feroensis it must be assumed that they are more frequent in E. and N. Iceland than is known at present, and as the latter species occurs in the Feerées, it may well be expected to be met with on other parts of the coast of Iceland.
MARINE ALGAL VEGETATION 57
With respect to the 6 species (A, 9—14) which have been found only in N. Iceland, it cannot be assumed that they are confined to the north coast, and it is highly probable that they have a much wider distribution on both sides. Dictyosiphon corymbosus and Ulo- thrix consociata v. islandica must, however, be assumed to belong more closely to E. and N. Iceland.
As regards the 8 species (A, 15—22) which occur so far west or south as NW. Iceland or SW. Iceland, it must be supposed that their absence trom N. Iceland (and E. Iceland /Ceratocolax, Cruoria/) is due merely to insufficient knowledge regarding their distribution. Of these species, those which extend to SW. Iceland have not been found, however, further south than in Breidifjéréur, with the ex- ception of Peyssonellia which has been found in Faxafléi near - Reykjavik.
Of the species given under A, Nos. 1—8, 12 and 14—23 must consequently be supposed to have an east-northward distribution along the coast of Iceland, while Nos. 9, 11 and 13 must be sup- posed to have some other principal distribution; one species (10) is endemic in the most western part of the north coast.
Under B, 53 species are recorded. Of these 10 have been found only in S. Iceland, the majority of these in the Vestmannaeyjar only; to these must be added Bonnemaisonia (31, p. 141) which I believe to have been found in S. Iceland. That is, 11 species in all, one of which, however, Rhodochorton repens, is endemic. 17 species have been found only in S. and SW. Iceland (B, 12—28) and 8 species in SW. Iceland only. Thus, there are in all 36 species which are known from S. and SW. Iceland only. 6 species (B, 37—42) have a more northern distribution, as they have been found in NW. Ice- land. Consequently, there are 42 species which are known only from S. and W. Iceland (NW. Iceland included), but of these species there are two, Cladophora rupestris and Codiolum Petrocelidis which probably have a more northern distribution. 10 species (B, 43-52) which have principally a south-western distribution (the fact that some of them have not been found in NW., SW. and S. Iceland is probably due to insufficient knowledge regarding their distribution) have been found also in N. Iceland. But all these species do not reach eastward along the north coast to the same extent, Ptilota plumosa and Corallina officinalis have been found furthest east in the eastern part of the north coast; Lithophyllum Crouani and Myrionema vulgare in Eyjafjéréur; Ahnfeltia and Petrocelis extend to
58 H. JONSSON
Skagafjéréur; while Cystoclonium, Polysiphonia nigrescens and Leathesia do not extend further than the most western part of the north coast (the small fjords in Hunafldi). Only Delesseria sanguinea now remains; strictly speaking, this appears to belong to the south and south-west coast, but has on one occasion been found in E. Iceland, cast up on the shore. It did not appear to have come from a distance, and it probably grows there, though I did not come across it in the dredgings.
Thus all these 53 species have on the whole a southern and western distribution in Iceland.
The above shows that there is a large neutral territory where the species with a south-western and those with a north-eastern distribution meet and intermingle. This boundary area comprises almost the whole of the north coast, the north-west fjords and, to a certain extent, the northern part of the south-west of the country. (For further details see below under the Floristic Boundaries.)
THE COMPONENTS OF THE ALGAL FLORA.
At present 200 species of Marine Algze are known from Iceland. In the plant-geographical groups established by Bérgesen and my- self (B6rgesen and Jénsson, 14) these are distributed in the following manner. The definition of the groups is here reproduced almost literally from the publication mentioned.
A. The Arctic Group.
The species of this group belong to the arctic area of the sea. The southern limit of this area extends from the north and east of Norway southward to the south-east point of Iceland, where the boundary is sharply defined. From E. Iceland the boundary line extends to the north of Iceland between Iceland and Greenland, and then turns considerably southward to the North Atlantic coast of America. The flora of the boreal area of the Atlantic passes without any distinct limit into the arctic algal flora on both sides of the Atlantic. In Iceland the limit is distinct only at the south- east point whereas the boundary is very indistinct on the north- east part of the coast.
Some of the species of this group occur, but only rarely, south of the border-zone.
MARINE ALGAL VEGETATION 59
Rhodophycee.
Ceratocolax Hartzii. Turnerella Pennyi.
Delesseria Baerii * corymbosa. Polysiphonia arctica.
Cruoria arctica. Lithothamnion flavescens. L. foecundum.
Pheophycee.
Omphalophyllum ulvaceum. Dictyosiphon corymbosus.
Laminaria nigripes.
Chlorophycee.
Monostroma groenlandicum.
B. The Subarctic Group.
Subdivision I.
The species of this subdivision are common in the Arctic Sea, and are rather common in the cold-boreal area of the Atlantic Ocean as far south as the Ferédes and Nordland; some of them occur, although rarely, as far south as England.
Rhodophycee.
Rhodophyllis dichotoma. Halosaccion ramentaceum. Ptilota pectinata. Rhodochorton penicilliforme.
Peyssonellia Rosenvingii. Lithothamnion tophiforme. i leeve:
Clathromorphum compactum.
Pheophycee.
Lithoderma fatiscens.
Ralfsia ovata.
R. deusta.
Myrionema globosum.
M. Laminarie.
Streblonema ecidioides. Sphacelaria britannica.
Cheetopteris plumosa. Coilodesme bulligera. Saccorrhiza dermatodea. Laminaria fzr6oensis.
L. digitata.
Alaria Pylaii.
Chlorophycee.
Chlorochytrium Schmitzii. Monostroma undulatum.
M. fuscum.
Ulothrix consociata v. islandica. U. subflaccida.
U. pseudoflacca. Acrocheete parasitica. Urospora Hartzii. Acrosiphonia hystrix. A. penicilliforme.
Subdivision II.
This subdivision includes species, which are either common in the Arctic Sea and the North Atlantic from western France— England northward, or which, if not common, are at least all equally frequent.
60 H. JONSSON
Rhodophycee. Porphyra miniata. Rhodymenia palmata. Conchocelis rosea. Delesseria sinuosa. Chantransia virgatula. Rhodomela lycopodioides. Phyllophora Brodizi * interrupta. Odonthalia dentata. Actinococcus subcutaneus. Ptilota plumosa. Euthora cristata. Lithothamnion glaciale. Pheophycee. Ralfsia clavata. Phzostroma pustulosum. Ectocarpus tomentosoides. | Dictyosiphon hippuroides. Leptonema fasciculatum v. subcylin- D. foeniculaceus. drica. Desmarestia viridis. Elachista fucicola. D. aculeata. Punctaria plantaginea. Chordaria flagelliformis. Litosiphon filiformis. Chorda tomentosa. Isthmoplea spherophora. C. filum. Stictyosiphon tortilis. Fucus inflatus.
Chlorophycee.
Chlorochytrium Cohnii. Pringsheimia scutata.
C. inclusum. Urospora mirabilis.
C. dermatocolax. U. Wormskioldii.
Codiolum gregarium. Chetomorpha Melagonium.
Percursaria percursa. Spongomorpha vernalis.
Monostroma Grevillei. Acrosiphonia incurva.
Ulothrix flacca. Cladophora rupestris.
Pseudendoclonium submarinum. C. hirta.
Bolbocoleon piliferum. C. sericea.
Ulvella fucicola. Ostreobium Queketti. Cyanophycee.
Pleurocapsa amethystea.
C. The Boreal-Arctic Group.
The species of this group are common in the Arctic Sea and the boreal area of the Atlantic at least as far south as the Atlantic coast of North Africa; probably some of them have a far greater southern distribution. Some of them might possibly be considered cosmopolitan. |
Rhodophycee. Bangia fuscopurpurea. Antihamnion Plumula v. boreale. Porphyra umbilicalis. Ceramium rubrum. Chantransia microscopica. Rhodochorton. Rothii. C. secundata. R. membranaceum.
Ahnfeltia plicata. Hildenbrandia rosea.
MARINE ALGAL VEGETATION 61
Pylaiella littoralis. Ectocarpus confervoides. E. siliculosus. Scytosiphon Lomentaria.
Enteromorpha intestinalis.
E. clathrata. Ulva lactuca. Chetomorpha tortuosa.
Spirulina subsalsa. Calothrix scopulorum.
Pheophycee. Phyllitis fascia. Fucus vesiculosus. Ascophyllum nodosum.
Chlorophycee.
Rhizoclonium riparium. Cladophora gracilis. Gomontia polyrrhiza.
Cyanophycee.
Rivularia atra.
D. The Cold-Boreal Group.
The species of this group have their area of distribution from
western France—England northward to S. Iceland,
the FeerG6es
and Nordland—Finmark. Some few species have occasionally been found in the Arctic Sea, especially in the White Sea and the Murman Sea, and some few reach as far south as the Mediterranean
and North Africa.
Porphyropsis coccinea. Chantransia Alariz. _ Gigartina mamillosa.
Phyllophora membranifolia. Cystoclonium purpurascens.
Lomentaria rosea. Delesseria alata.
D. sanguinea. Polysiphonia urceolata: P. fastigiata.
P. nigrescens. Callithamnion Arbuscula. Plumaria elegans. Antithamnion floccosum.
Ceramium acanthonotum.
C. Deslongchampii.
Petroderma maculiforme.
Ralfsia verrucosa. -Myrionema vulgare. M. Corunne.
M. feerodense.
Rhodophycee.
Ceramium fruticulosum.
C. circinnatum.
C. altanticum.
Rhodochorton repens.
R. minutum.
Dumontia filiformis.
Dilsea edulis.
Petrocelis Hennedyi. Rhododermis parasitica. Lithothamnion Ungeri.
L. Lenormandi. Phymatolithon polymorphum. Lithophyllum Crouani. Dermatolithon macrocarpum. Corallina officinalis.
Phzeophycee.
Ascocyclus islandicus.
Microsyphar Polysiphonie. Streblonema Stilophore v. czespitosa. Ectocarpus tomentosus.
E. penicillatus.
62 H. JONSSON
Ectocarpus fasciculatus. Castagnea virescens. E. Hinksie. Laminaria saccharina. Sphacelaria radicans. L. hyperborea. S. olivacea. Fucus spiralis. Phyllitis zosterifolia. F. serratus. Dictyosiphon Ekmani. Pelvetia canaliculata. D. Mesogloia. Alaria esculenta. D. Chordaria.
Chlorophycee. Codiolum Petrocelidis. Entoderma Wittrockii. C. pusillum. Acrochete repens. Enteromorpha aureola. Ochlocheete ferox. Prasiola polyrrhiza. Acrosiphonia albescens. P. furfuracea A. flabelliformis. P. stipitata. Cladophora glaucescens.
Cyanophycee. Plectonema norvegicum.
E. The Warm-Boreal Group.
The majority of the species referred to this group extend at least as far south as the Mediterranean and the Atlantic coast of North Africa. According to the different distribution northward the group is divided into three parts of which only the one reaches as far north as S. Iceland.
1. Species extending as far north as S. Iceland, the Ferées and Northern Norway, and at least as far south as the Mediterranean and North Africa.
Rhodophycee. Chondrus crispus. Callithamnion scopulorum. Lomentaria clavellosa. Ceramium arborescens. Plocamium coccineum. Cruoria pellita.
Bonnemaisonia asparagoides. Pterosiphonia parasitica.
Pheophycee. Desmarestia ligulata. Leathesia difformis. Chlorophycee. Enteromorpha Linza. Cyanophycee.
Phormidium autumnale.
According to the above the number of species in the groups Is as follows: — |
MARINE ALGAL VEGETATION 63
Rhodo- Phzeo- Chloro- Cyano- phyceze phyceze phyceze phyceze
ine arctic sroup..... J J 1 >» =11species (5.5°/o) 2. The subarctic group:
Subdivision I.:...... 8 13 10 mo == SA (155° /0) 3. The subarctic group:
Subdivision Il....:.. 12 19 20 1 = 50° — «(25.09 /o) 4. The boreal-arctic group 10 7 ji Br aaa Dey em. Aye gy) 5. The cold-boreal group. 31 25 12 ti 690-450) 6. The warm-boreal group 8 2 i Bo 12 = (G08 /p}
76 67 51 6
If we divide the six groups into two parts, A: the first three groups, and B: the last three! groups, we obtain the following figures: —
A, 92 species (46 °/o) and B, 108 species (54 °/o).
The floral district must therefore be determined as boreal, be- cause more than half of the species belong to the last three groups. Of these groups the cold-boreal is the most important because its species form 64°/o of the total number of species (108) in all three groups. This floral district has not, however, a purely boreal cha- racter, as the subarctic group is rich in species and gives a rather high percentage (41 °/o). The floral district, then, is characterized to a very high degree by a boreal element, and next by a subarctic element.
If we consider only the red and the brown algz, 143 species in all, the cold-boreal character is a little more strongly pronounced than the subarctic. The figures are: — Arctic 10 species (7 °/o), sub- arctic 50 species (35 °/o), boreal-arctic 17 species (12 °/o), cold-boreal 56 species (39 °/o) and warm-boreal 10 species (7 °/o). The first three groups have 60 species (42 °/o), the last three 78 species (58 °/o).
If we compare the five divisions of the coast with respect to the number of species in the different groups, we obtain the figures given in Tables 3, 4. |
If, for instance, we select the red and the brown alge (Table 4) as a basis, then the difference which exists in the different parts of the coast is very evident. In E. Iceland the arctic group contains the greatest number of species, and this number — if we follow the divisions of the coast in the order of the tables — decreases
1 The boreal-arctic group is included in the boreal groups, as its species,
though common in the arctic district, have a far larger area of distribution out- side this.
64 H. JONSSON
Table 3. Red alge, Brown alge, Green algz, Blue-green alge
collectively. | !
E. Icel. N. Icel. NW. Icel. | SW.Icel. | S. Icel.
a 3g 3| = s ees site ESS; % | 9°38) % Eos % Eos % | §°3 %y Z a | 4 zal iA a Za zy Oo : Arctic group... 0. tne. 8 | 7 SP ek 3 3 2 1 > > Subarctic group I...... 25 22 2 20 VGA abil 2 ie ee 12) Subarctic group Il..... | 38| 34] 37] 30].39 | 41,]| 44] 98 | Om eae Boreal arctic group....! 20 | 18 260° Deal 1G Ly 23 | 15 16 |} 15 Cold-boreal group...... | 20 | 18] 29.| 24] 18 | 20] 53] 34 | 43 | 39 Warm-boreal group....| 1 ¢1) 2 |e Pa Bi crap a ea 4 9 9
aa eee a Total, | 2) aes hh aa 155 108
Table 4. Red and Brown alge collectively.
Tl I 3 | E. feel}. Nueel... ||, NWi cel, |) SW. Teel.) Siieet (2.2 o/ \3_2 0 2.2 0 \3.3 0 ER 0/ |Eog /o Beg /o Fog lo Sor lo 5 Ome 1A @ Zw a @ ae a3 Cae Arctic proup.) i.a04e00) Wes} 8 | 4] 5 | 2y)'| wes epee 2 > > Subarctic group 1...... | 18 | 23 | 19 | 22 093 | 18 |, 200) am 8 | 10 Subarctic group II..... | 25 31 24 28 Dias 37 26 | 23 17) 20 Boreal arctic group.... | PS A DGrs te LT | 19. || 13.) 18. |. 2G.) TASS ies | 15 Cold-boreal group...... | 17, | 21 | 21.) 24]. 16 | 92 || .46 | AON eee Warm-boreal group....| > > Dea a hy ao eee 8 10 | | | | | Total...) 80 | 87 [pda anes | 8 |
uniformly in the other parts of the coast, and is reduced to 0 in S. Iceland. In E., N., NW. and SW. Iceland the number of the species in the subarctic group I is practically identical in propor- tion to the number of species, taken as a whole, in these parts of the coast; S. Iceland has a distinctly smaller number, only 10 °/o. The subarctic group II is represented most abundantly in NW. Ice- land; E. and N. Iceland come next; but S. and SW. Iceland have a considerably lower percentage (about 20 °/o). The percentage in the boreal-arctic group is practically identical in all parts of the coast. The cold-boreal group presents almost the same percentage in E., N. and NW. Iceland, while the percentage in the group in
MARINE ALGAL VEGETATION 65
SW. and S. Iceland is almost double this. The warm-boreal group is not represented in E. Iceland, and only with extreme rarity (1 species) in N. and NW. Iceland. SW. Iceland has only 4 species, while S. Iceland has 8 (10 °/o).
There is a very great similarity between S. Iceland and SW. Iceland, if the arctic group in SW. Iceland is excluded; on the other hand, the difference is greatest between E. Iceland and S. Iceland, as is shown by the following figures: —
East Iceland South Iceland
PRE? OROMG coco. gcse: 2. fe ts 9 %/o 0 °/o subarctic eroups 20h. 54 %/o 30 °/o Boreal-arctic ‘group's ...) 0.0 - 16 °/o 15 %/o Cold boreal erowp i, .yii./.\s.. 08 eee os 7 Veer fe 45 °/o iiamn-boreal Sronp . 0 o6 cj... 0 °%/o 10 °/o
If we assume that the species marked (c) (Table 1) are to be considered as common to all parts of the coast (see above), the distribution of the 76 not-common species becomes decisive with reference to the floristic difference between the parts of the coast. In the following table, therefore, it is shown how these 76 species are arranged in the six plant-geographical groups of alge.
Table 5. Group-division of the 76 not-common species (see Table 2).
A E. Icel. | N. Icel. [NW.Icel.|SW. Icel.| S. Icel. | B
\|
| Arctic group.
MECC STOUP ......-.- 8 5 3 DAs } se hate | | Subarctic group I. Subaretic group I.... || 5 3 EL. me ae | 1 7st ane 2 | Subarctic group II. Subarctic group II1.... 2 Be 2 | lip, oat 1 LES ar 1 | Boreal-arctic group. Boreal-arctic group... | .. a BPS NG m| hea oa 6 8 31 | 28 | Cold-boreal group. Cold-boreal group .... is 4 ee | | 2 2 6 9 | Warm-boreal group.
Warm-boreal group... ae Si i oe am ial f 10 13 40 | 40 | Total number ofspecies Total number of species | 15 (9 +4 Sip ly 25
16 23 21 | 45 | 40
|
The figures in this table show what has been already shown by those which I have given in Tables 3 and 4; but the arctic
The Botany of Iceland. I. 5
66 H. JONSSON
element in E. Iceland and the boreal element in S. and SW. Iceland are much more sharply defined; and this is natural, as the species assumed to be common are omitted. Even if we consider: only the known distribution of the species, in its entirety (see Table 1), the distribution of the here-mentioned 76 species will still be the most essential reason for the floristic difference between the parts of the coast.
The species assumed to be common are 124 (see above). Of these none are arctic, 25 belong to the subarctic group I, 46 to the subarctic group II, 26 are boreal-arctic, 26 cold-boreal, and one (Phormidium autumale) is warm-boreal. Of the 76 not- common species, 11 are arctic, 6 belong to the subarctic group I, 4 to the subarctic group II, one (Ahnfeltia plicata) is boreal-arctic, 43 are cold-boreal and 11 warm-boreal. If we add together the numbers representing the species of the corresponding groups as regards the 124 species assumed to be common and the 76 not-common species (Table 5), and compare with Table 3, we find that the species are more numerous in each district, but that the percentages are almost the same.
If the groups are divided in two parts, A and B (see above) so that A includes the arctic and subarctic groups, and B the three other groups, the following figures are obtained (see Table 4): —
E. Icel. N. Icel. NW, Icel. SW. Icel. S. Icel. A:... 50(63%o) 47(54°%/o) ~ 42:68 °%/0) 48:42 %o) Seana B.... ) 30(87.%/0) 40 (46 °%/o) 31 (42%) 67 (58/0) aOrG@ te a
The arctic group is poorly represented in all the districts of the coast (see Table 4) and therefore the figures mentioned above under A apply chiefly to the subarctic group; the floral districts of KE. Iceland, N. Iceland and NW. Iceland are thus subarctic. E. Ice- land is subarctic to a greater extent than N. and NW. Iceland. SW. Iceland is a boreal floral district with a very considerable subarctic element, and thus resembles the coasts of Iceland taken as a whole (see above). S. Iceland is a boreal district with a slightly subarctic element.
Floristic Boundaries.
The mixed character of the flora in N. and NW. Iceland has been alluded to several times in the foregoing pages, and is clearly seen from the tables given, as, for example, Tables 2 and 5. Here
; b)
MARINE ALGAL VEGETATION 67
neither, is any distinct boundary found between the boreal and subarctic floral districts, and the north and north-west of the country must, strictly speaking, be considered a large boundary-area, a view which accords well, also, with the hydrographic conditions. Here, the boreal, subarctic and arctic species intermingle.
At the south-eastern point of Iceland there is, on the other hand, a rather distinct hydrographic boundary along the stretch from Vestrahorn to Eystrahorn (or Lonsheidi). The greater part of this coast is sandy, and difficult of access for the investigation of the algal vegetation. From my own observations I can only say that Berufjordur, the most southerly point in E. Iceland which I have examined with regard to its algal vegetation, has a cold-water flora, and that the Vestmannaeyjar, the most easterly locality on the south coast which I have examined for the same purpose, have a warm-water flora. The boundary must lie between them, and I conclude, especially from the hydrographic conditions and the dis- tribution of the Plankton-associations, that it is situated just on the stretch of coast already mentioned. Ove Paulsen (55 and 56) has given valuable information respecting this boundary, and it is evident from his investigations that the boundary varies to a slight extent, the facts being that in May-June it has been found in the vicinity of Eystrahorn (see 55, map J), but in July-August at Vestra- hern (see 55, map Ii). If alge grow on this stretch of coast, one may conclude that there exists a mixed flora resembling that of N. and NW. Iceland. Whether boreal species can be carried to E. Iceland in this manner is at present not easy to say with certainty, yet it seems to me that the occurrence of Dumontia filiformis and Delesseria sanguinea, both of which are absent in N. and NW. Ice- land, can be most easily explained in this way.
IV. COMPARISON WITH NEIGHBOURING FLORAL DISTRICTS.
l° Table 61 is given a survey of the plant-geographical distribu- tion of red and brown alge collectively, in certain subarctic and boreal floral districts. These are so arranged that those floras with the largest arctic element stand furthest to the left. The arctic and subarctic percentages decrease while the boreal percentage increases to the right. The boreal-arctic group is practically similar everywhere, which is also natural according to the geographical dis- tribution of the group. The warm-boreal group is not represented in the subarctic floras, and the arctic group is quite infinitesimal in SW. Iceland and Nordland, and is entirely absent from S. Iceland and the Feerédes. In regard to species, the cold-boreal group is ex- tremely poor in East Greenland and Spitzbergen, somewhat richer in West Greenland and considerably richer in E. Iceland.
By grouping the species, as is done above (cf. B6rgesen and Jonsson, 14), the character of the floral districts can be deter- mined according to those groups which are richest in species. Thus, I characterize a group as subarctic when more than half of its species are reckoned to the subarctic group. In a similar manner a district is boreal when more than half of its species belong to the boreal groups (bor. arct., cold-bor., and warm-bor.).
Similarly, in an arctic district the species belonging to the arctic group must constitute more than half of the number of species be- longing to the district, and, in addition to the subarctic group, only the boreal-arctic will be represented. Of the floral districts men- tioned by Bérgesen and Jénsson (14) none are arctic according
* With the exception of Iceland the numbers of the species of red and brown
alge are taken from Bérgesen and Jénsson l.c. (14, p. 22). In regard to East -
Greenland the numbers are corrected according to Rosenvinge (64), and to West Greenland two species have been added: Ectocarpus maritimus and Chantransia collopoda.
\
H. JONSSON: MARINE ALGAL VEGETATION 69
to the definition here employed. The Siberian Sea, however, comes nearest to it. From here 23 species are known (14), of which 9 (39 °/o) are arctic, 11 (48 °/o) subarctic and 3 (13 °/o) boreal- arctic. This district is at the boundary between arctic and sub- arctic. Regarded superficially it may appear strange that none of the districts are arctic, but on closer inspection this is easily under- stood, the reason being that some of the districts (14) are too large and consequently acquire a mixed character. In this respect I shall merely point out, for instance, that both Spitzbergen and East Greenland (and probably West Greenland) ought to be divided into two districts.
As already mentioned, none of the districts recorded in Table 6 is arctic. East Greenland, Spitzbergen and West Greenland have almost the same percentage as regards the arctic species (Table 6), and as this percentage is rather high in proportion to that of the boreal species, these districts could be termed arctic-subarctic, in contra- distinction to E. Iceland where the arctic percentage is four times less than the percentage of the boreal species. The boreal districts recorded here (Table 6, p. 70) should, strictly speaking, be called cold-boreal.
If we call the first three groups (in Table 6) A and the three last B the percentages will be as follows: —
E.Greenl. Spitzb. W.Greenl. E. Icel. Finm. SW.'Icel. S. Icel. Feer. Nordl. | ee, a 81 ra 72 63 46 42 30 29 20 Boe ee. : 19 23 28 ah 54 28 70 @1 73
As the table shows, SW. Iceland agrees most closely with Fin- mark, while S. Iceland and the Ferdées are nearly alike, as Borge- sen (12, p. 804) also supposes.
If we take Iceland as a whole, we get 143 species (red and brown alge collectively), 10 (7 °/o) arctic, 21 (15 °/o) subarctic (sub- division I), 29 (20 °/o) subarctic (subdivision II), 17 (12 °/o) boreal- arctic, 56 (39 °/o) cold-boreal and 10 (7 °/o) warm-boreal. These figures are almost the same as those given for Finmark (see Table 6) and differ, essentially from the figures given for SW. Iceland,. only by the higher percentage of arctic and warm-boreal species. If, on the other hand, we take the first three groups collectively and the three last groups in a similar manner, we obtain the same percentages as for SW. Iceland. On combining different parts of the’ coast, as for instance, E. Iceland and N. Iceland, we get almost the
in certain Subarctic and Boreal flora! districts.
Table 6. Distribution in groups of Red and Brown algz collectively
ATGUE-SLOUP: oe). «ec. ee: Subarctic group I.....
Subarctic group II....
la
H. JONSSON
Subarctic group I-+ II Boreal-arctic group.... Cold-boreal group.....
Warm-boreal group...
70
Subarctic
Boreal
East Spitz- West . : : hes,
Grecai: bergen Crean 3 E. Icel. Finmark || SW. Icel. S. Icel. Feer oes Nor dland mf Be an ar my ee oA een Bon ean eae) oe a4 alee oe Blac ae Bless a8 ee Bee) Mo ESR) Mo ESR Me BS) Mh | Ser Eee Peel eee a) Le el Zz 2 Zoe inna Z 2 Za 2 Zo a Z 2 Ze 7. ye)
. 15 18 10 7 18 9 y 6 2 2 ae Bm Kg eae 1 1 ; 26 30 14 2S} 26 Te Oe [erty 20 | 17 8 10 14 9 12 | 10 : 28 33 22 oY 28 St 29m 23 26 | 23 lye 20 31 | 20 20 | 16 ‘ 54 63 36 60 54 54 50 | 40 46 | 40 25 30 45 29 Se exh) : 12 14 i) 15 16 16°] 18) 14 16 | 14 13 15 Lee ae 16 | 13 ‘ 4 5 5 8 12 21 45 | 36 46 | 40 38 45 15a) Ad 61 | 49 5 Ber = tM ”, sae bie 5 4 5 4 8 10 20 | 13 Spel Total. 85 60 125 115 84 157 123
eS eS SS SS SE SS SS
1 According to Petersen ‘57) 2 species of Ceramium (C. Areschoughii [assigned to the subarctic group II] and C. septentrionale [assigned to the arctic group|) have here been added to West Greenland. To the Ferées have been added Ceramium Boergesenti and
Ceramium atlanticum, both of which I assign to the cold-boreal group.
MARINE ALGAL VEGETATION Eig |
same figures as for E. Iceland, and on combining NW., SW. and S. Iceland we get almost the same figures as for SW. Iceland. E. Iceland and N. Iceland have 101 species of red and brown alge collectively. Of these 8 (8 °/o) are arctic, 20 (20 °/o) subarctic (sub- division I), 28 (27 °/o) subarctic (subdivision II), 17 (17 °/o) boreal- arctic, 26 (26 °/o) cold-boreal and 2 (2 °/o) warm-boreal. NW., SW. and S. Iceland have 131 species of red and brown algz collectively. Of these 3 (2 °/o) are arctic, 20 (15 °/o) subarctic (subdivision I), 29 (22 °/o) subarctic (subdivision II), 16 (12 °/o) boreal-arctic, 53 (41 °/o) cold-boreal and 10 (8 °/o) warm-boreal.
As regards the components of the flora, both Iceland taken as a whole, and SW. Iceland resemble Finmark; S. Iceland resembles the Fer6ées and Nordland, and E. Iceland resembles the White Sea.!
It is evidently not.due to chance that the resemblance of the floral districts happens thus. The situation of Iceland just south of and at the boundary between the arctic and the cold-boreal districts corresponds exactly with the situation of Nordland—Finmark— White Sea in relation to this boundary. Iceland and the White Sea are at the boundary itself, and in Finmark it certainly will be possible to distinguish parts of the coast with a similar mixed flora as in N. and NW. Iceland; the southern part of Finmark will then be something like SW. Iceland, while S. Iceland, as already mentioned, corresponds with Nordland.
This comparison shows only the relation between the quantity of the species of the floral districts within the different groups, but gives no information as to how far the species are common to all those districts. Then it remains to be investigated how many species Iceland has in common with the other districts. At the present time a comparison of the floras will, however, scarcely give any satisfactory results, because all the districts in question are not equally well-known. By future investigations a greater number of species will unquestionably be found in the majority of the floral districts, and the quantity of the species will thus be altered, but the relation between the number of the species of the different groups will, however, undoubtedly remain unaltered.
1 According to Bérgesen and Jénsson (14) 52 species are known from the White Sea, of which 3 (6 °/o) are arctic, 10 (19 %/o) subarctic (subdivision I), 19 (37 %/o) subarctic (subdivision II), 8 (15 %/o) boreal-arctic and 12 (23 °/o) cold-boreal. The subarctic species constitute 56 °/o of the entire number of species and the
character of the flora is consequently subarctic in the same degree as that of E. Iceland.
72 H. JONSSON
If we compare S. Iceland and the Fzrées with regard to common species, the following figures are obtained: —
South Iceland 84 species? The Feer6es 157 species not common common not common 10 (6 °/o) 74 (44 °/o) 83 (50 °/o)
Here it should be noted that S. Iceland is so very little known that one is scarcely justified in comparing it with such a well in- vestigated district as the Ferées. Many of the species which in this respect are peculiar to the Feerdes will certainly be found in S. Iceland and, at any rate, 32 of them are known from other parts of Iceland, principally from SW. Iceland.
If we choose a larger district of the coast of Iceland, for in- stance, the boreal district (S. Iceland and SW. Iceland) for compa- rison with the Ferées, the following figures will be obtained: —
S. and SW. Iceland 126 species The Ferées 157 species not common common not common 25 (14 7/0) 101. (55 °/o) 56 (31 °/o)
On comparing Iceland with the Ferées we obtain the following figures: —
Iceland 143 species The Feerées 157 species not common common not common 37 (19 °/o) 106 (55 °/o) 51 (26 °/o)
The 37 species which grow in Iceland and are absent from the Ferées are the following: —
fChantransia microscopica. +Petrocelis Hennedyi.
Ceratocolax Hartzii. Cruoria arctica.
Turnerella Pennyi. tPeyssonellia Rosenvingii.
Delesseria Baerii. +Rhododermis parasitica.
Bonnemaisonia asparagoides. Lithothamnion flavescens.
Polysiphonia arctica. L. foecundum.
Ceramium Deslongchampii. rL. tophiforme.
C. fruticulosum. TL. Ungeri.
C. circinnatum. fRalfsia ovata.
C. arborescens. R. deusta. fRhodochorton minutum. fMyrionema Laminarize 7R. repens. rAscocyclus islandicus. TDilsea edulis. tEctocarpus penicillatus.
* These and the following figures apply to red and brown algz collectively. * I attach no importance to the fact of this species having occurred in Ice- land, as it has not yet been found again.
MARINE ALGAL VEGETATION 73
TSphacelaria radicans. TDictyosiphon Chordaria. TS. olivacea. D. corymbosus. Omphalophyllum ulvaceum. Saccorrhiza dermatodea. fPheostroma pustulosum. Laminaria nigripes. Coilodesme bulligera. fFucus serratus.
fDictyosiphon Mesogloia.
Which of these species may be found in the Ferdées is not easy to decide (cf. also Borgesen, 12, p. 795). But it does not appear altogether improbable that 19 species (marked with a + before the name) could occur there.
The 51 Feerdese species which are not found in Iceland are the following: —
fErythrotrichia ceramicola. +Rhododermis elegans. tPorphyra leucosticta. Phymatolithon levigatum. 7Chantransia efflorescens. Lithophyllum incrustans. TC. Daviesii. _L. hapalidioides.
Choreocolax Polysiphoniz. rSorapion Kjellmani. tHarveyella mirabilis. fMyrionema foecundum. Callophyllis laciniata. 7M. speciosum.
Callocolax neglectus. . rChilionema reptans. Sterrocolax decipiens. Microsyphar Zostere. fLomentaria articulata. Ectocarpus velutinus.
Nitophyllum laceratum. TE. lucifugus.
Laurencia pinnatifida. E. dasycarpus.
Polysiphonia violacea. E. granulosus.
TP. Brodizi. Elachista scutulata. TP. elongata. Sphacelaria czspitula.
P. atrorubescens. S. furcigera.
Rhodomela subfusca. TS. cirrhosa.
Griffithsia setacea. Cladostephus spongiosus. 7Callithamnion polyspermum. Desmotrichum undulatum. TC. corymbosum. Punctaria latifolia.
C. granulatum. yAsperococcus echinatus. 7Ceramium Boergesenii. yLitosiphon Laminarie.
Rhodochorton seiriolanum. +Phzeostroma parasiticum. 7Furcellaria fastigiata. y7Himanthalia lorea. fPolyides rotundus. ;Halidrys siliquosa.
7Cruoriella Dubyi.
Possibly many of these species, perhaps almost half of them, are to be found in S. and SW. Iceland. The 26 species marked with a + before the name may possibly be found in Iceland, though with many of them this is doubtful.
If it should appear from further investigations that some of the species considered not common to the Feerées and Iceland are com- mon to them, it should not be assumed from this that the floristic
74 H. JONSSON
resemblance is increased, as it is highly probable that other species which are not common would be simultaneously found.
From the coast of Norway I select Finmark for comparison with Iceland, which comparison gives the following figures: —
Iceland 143 species Finmark 125 species not common common not common 45 (26 °/o) 98 (58 °/o) 27 (10)! 70)
A comparison between Finmark and SW. Iceland gives the following figures: — |
SW. Iceland 115 species Finmark 125 species not common common not common 7h es AS ch) 86 (56 °/o) 39 (25 °/o)
The following are the 45 species which are found in Iceland and are absent from Finmark: — |
1 Porphyropsis coccinea. 24 Ralfsia ovata.
2 Chantransia Alarie. ; 25 R. clavata.
3 Phyllophora membranifolia. 26 R. verrucosa.
4 Ceratocolax Hartzii. 27 Myrionema Lamimarie. 5 Lomentaria rosea. 28 M. Corunne.
6 L. clavellosa. 29 M. globosum.
7 Plocamium coccineum. 30 M. feerdense.
8 Delesseria Baerii. 31 Ascocyclus islandicus.
9 Bonnemaisonia asparagoides. 32 Microsyphar Polysiphonie. 10 Pterosiphonia parasitica. 33 Ectocarpus Stilophore. 11 Callithamnion Arbuscula. 34 E. tomentosoides.
12 Ceramium acanthonotum. 35 E. tomentosus.
13 C. fruticulosum. 36 E. Hinksie.
14 C. arborescens. 37 Sphacelaria radicans.
15 C. atlanticum. 38 S. olivacea.
16 Rhodochorton minutum. 39 Omphalophyllum ulvaceum. 17 R. repens. 40 Litosiphon filiformis. — 18 Dilsea edulis. 41 Phzostroma pustulosum. 19 Petrocelis Hennedyi. 42 Phyllitis zosterifolia.
20 Cruoria arctica. 43 Dictyosiphon Mesogloia. 21 C. pellita. 44 Desmarestia ligulata.
22 Rhododermis parasitica. 45 Laminaria feroensis.
23 Petroderma maculiforme.
Of these species ten (Nos. 3, 6, 7, 10, 11, 12, 18, 21, 26 and 35) are known from Nordland and therefore might possibly be found also in Finmark. Furthermore, nine of the species (Nos. 2, 5, 9, 25, 33, 34, 35, 40, 44) are known from West Norway, and the majority of these will also be found, without doubt, in Nordland and Fin- ©
MARINE ALGAL VEGETATION 75
mark. Of the remaining 23 species the greater number will cer- tainly be found in Finmark. But I| think it less probable that Om- phalophyllum ulvaceum and Laminaria feréensis are to be met with there, while one can form no opinion as to whether the endemic Icelandic species (17 and 31) exist in Finmark, as their distribution outside Iceland is unknown. On the other hand I think it somewhat probable that the Icelandic-Feréese species Myrionema fcréense may occur in Finmark.
The 27 species, which are present in Finmark and absent from Iceland, are the following: —
Chantransia efflorescens. . Ectocarpus terminalis. C. Daviesii. — E. nanus.
Harveyella mirabilis. E. ovatus. Polysiphonia elongata. Myriotrichia filiformis. Spermothamnion Turneri. Sphacelaria racemosa. Furcellaria fastigiata. S. cirrhosa.
Polyides rotundus. Pheosaccion Collinsil. Petrocelis Middendorfii. Asperococcus echinatus. Phymatolithon investiens. Delamarea attenuata. Lithothamnion intermedium. Dictyosiphon hispidus. L. fornicatum. Laminaria Agardhii. Lithoderma lignicola. Haplospora globosa. Myrionema foecundum. Halidrys siliquosa.
Chilionema reptans.
The majority of these species may be expected to occur on the coasts of Iceland, but there is less probability of Laminaria Agardhi being met with there.
If we turn to E. Iceland and compare this with the White Sea we obtain the following figures: —
E. Iceland 80 species White Sea 52 species not common common not common 43 (45 °/o) 37 (39 °/o) 15 (16 °%o)
The floristic similarity is somewhat considerable, and ten of the species peculiar to the White Sea are known from other parts of the coast of Iceland. These ten species are Dilsea edulis, Cysto- clonium purpurascens, Polysiphonia nigrescens, Delesseria alata, Ptilota plumosa, Lithothamnion Lenormandi, Corallina officinalis, Dictyo- siphon hippuroides, Fucus serratus, and Pelvetia canaliculata.
Of these species, however, only an extremely small number can be expected to occur in E. Iceland.
The five species present in the White Sea and entirely absent from Iceland are: —
76
Chantransia efflorescens. Furcellaria fastigiata. Polyides rotundus.
Sphacelaria racemosa. Laminaria Agardhii.
With the exception of Laminaria Agardhi all these species certainly may be met with on the coasts of Iceland, but in E. Ice- land one can scarcely expect to find others than Chantransia efflo-
rescens and Sphacelaria racemosa.
If we compare Iceland and E. Iceland with West Greenland and East Greenland we get the following figures: —
Iceland 143 species
not common common 62 (36 °/o) 81 (48 %/o) Iceland 143 species not common common 79 (48 °/o) 64 (39 °/o) E. Iceland 80 species not common common 11 (9 °/o) 69 (58 °/o) E. Iceland 80 species not common common 23 (21 °/o) 57 (53 °/o)
West Greenland 108 species
not common 27 (16 °/o) East Greenland 85 species not common 21 (13 %/o)
West Greenland 108 species
not common 39 (33 °/o) East Greenland 85 species | not common 28 (26 °/o) .
The species present in Iceland and absent from West Greenland
are the following: —
Porphyropsis coccinea. Chantransia Alariz. Phyllophora membranifolia. Ahnfeltia plicata.
Chondrus crispus. Gigartina mamillosa. Cystoclonium purpurascens. Lomentaria rosea.
L. clavellosa.
Plocamium coccineum. Delesseria alata.
D. sangvinea.
Bonnemaisonia asparagoides.
Polysiphonia fastigiata.
P. nigrescens. . Pterosiphonia parasitica. Odonthalia dentata. Callithamnion scopulorum. C. Arbuscula.
Plumaria elegans.
Ptilota plumosa.
Ceramium acanthonotum.
C. Deslongchampii.
C. fruticulosum.
C. circinnatum.
C. arborescens.
C. atlanticum. Rhodochorton minutum.
R. repens.
Dumontia filiformis.
Dilsea edulis.
Petrocelis Hennedyi.
Cruoria_ pellita.
Rhododermis parasitica. Phymatolithon polymorphum. Lithothamnion Lenormandi. L. flavescens.
L. Ungeri.
Lithophyllum Crouani. Dermatolithon macrocarpum.
MARINE ALGAL VEGETATION a7
Corallina officinalis. Dictyosiphon Ekmani. Petroderma maculiforme. D. Mesogloia.
Myrionema Laminarie (in E.Greenl.) Desmarestia ligulata.
M. vulgare. Leathesia difformis.
M. Corunne. Laminaria saccharina (in E. Greenl.) M. feeroense. L. feerdensis.
Ascocyclus islandicus. L. hyperborea.
Ectocarpus tomentosus. Alaria esculenta (in E. Greenl.) E. fasciculatus. Fucus spiralis.
E. Hinksie. F. serratus.
Sphacelaria olivacea. Pelvetia canaliculata.
Of the 57 species here mentioned three are found in East Green- land; viz. Myrionema Laminarie, Laminaria saccharina and Alaria esculenta. It is most probable that none of these 57 species will be met with in West Greenland, with the exception, perhaps, of some of the Myrionema-species.
There are 74 species absent from East Greenland which are found in Iceland. Of these, 54 species have already been mentioned (see above), and to these must be added 20 species which are absent from East Greenland but present in West Greenland and Iceland. These species are the following: —
Bangia fuscopurpurea. Ectocarpus Stilophore. Porphyra umbilicalis. E. tomentosoides. Chantransia secundata. E. penicillatus.
C. virgatula. Sphacelaria radicans. Polysiphonia urceolata. Litosiphon filiformis. Antithamnion floccosum. Phyllitis zosterifolia. Ceramium rubrum. Dictyosiphon Chordaria. Ralfsia ovata. D. corymbosus.
R. verrucosa. D. hippuroides. Microsyphar Polysiphonie. Castagnea virescens.
It seems most probable that these 20 species are to be met with in East Greenland.
The 11 species present in E. Iceland and absent from West Greenland are included in the above-mentioned figure. They are: —
Gigartina mamillosa. Laminaria saccharina (in E. Greenl.) Delesseria sangvinea. 3 L. feerdensis.
Odonthalia dentata. L. hyperborea.
Dumontia filiformis. Alaria esculenta (in E. Greenl.) Lithothamnion flavescens. Fucus spiralis.
L. Ungeri.
The 23 species present in E. Iceland and absent from East Green- land have also been already recorded. With the addition of the 9 of the above-mentioned species they are the following: —
78 H. JONSSON
Bangia fuscopurpurea. Ectocarpus tomentosoides. Porphyra umbilicalis. E. penicillatus. Chantransia secundata. Sphacelaria radicans. Polysiphonia urceolata. Litosiphon filiformis. Antithamnion floccosum. Phyllitis zosterifolia. Ralfsia verrucosa. Dictyosiphon Chordaria. Ectocarpus Stilophore. Castagnea virescens.
These species might possibly also be found in East Greenland, as they are already known from West Greenland (see above), and in that case there could be only 9 E. Iceland-species which were not known from East Greenland.
In West Greenland there are 27 species which are not found in Iceland. These are: —
@ Harveyella mirabilis. M Sphacelaria racemosa. Callymenia sangvinea. Pheeosaccion Collinsii. Delesseria Montagnei. @ Symphyocarpus strangulans. Polysiphenia elongata. Kjellmania subcontinua. Ceramium Areschoughii. Coelocladia arctica.
C. septentrionale. @ Delamarea attenuata.
® Rhododermis elegans. Dictyosiphon hispidus. Lithothamnion intermedium. Myriocladia cailitricha. Chantransia collopoda. @ Laminaria solidungula.
@ Sorapion Kjellmani. © L. longicruris. Ectocarpus Pringsheimii. L. cuneifolia.
@ E. ovatus. @ L. groenlandica.
@ E. pycnocarpus. @ Agarum Turneri.
-@ E. maritimus.
Of these species 13 (with @ prefixed) are found in East Greenland.
In East Greenland 21 species are found which are not known from Iceland. In addition to the 13 above-mentioned species, they are the following: —
Chantransia efflorescens. Ectocarpus helophorus. Dilsea integra. Haplospora globosa. Petrocelis polygyna. Punctaria glacialis. Cruoriopsis: hyperborea. Myrionema foecundum.
The greater number of the West Greenland and East Greenland species here mentioned will probably be met with in Iceland, espe- cially on the north and east coasts. It is less likely, however, that the following species will be found in Iceland: — Callymenia sanguinea, Delesseria Montagnei, Dilsea integra, Petrocelis polygyna, Laminaria solidungula, L. cuneifolia, L. groenlandica and Agarum Turneri.
According to the above comparisons Iceland most nearly resembles Finmark, and next to that place the Feerées; the resemblance to West
MARINE ALGAL VEGETATION 79
Greenland is rather less, and to East Greenland is least of all, as the following figures show: —
common not common keceland —Pinmark::. «...-..:..- 58 °%/o 42 %7/o feclaud——the -F2eroes .. 6. sass) es 55 °/o A5 %o Iceland—West Greenland ....... A8 9/9 52 %o Iceland—East Greenland........ 39 %o 61 °/o
S. Iceland is too little known to be compared with other districts, as has already been emphasized above. The resemblance to the Fer6des will certainly prove to be much greater than is shown by the figures now known.
common not common S. Iceland—the FeerGes ......... 44 9/9 56 °/o - §. and SW. Iceland—the Ferées. 55 °/o 45 %/o
S. Iceland and SW. Iceland together resemble the FerGées to the same degree as do the coasts of Iceland taken as a whole. The fact that S.Iceland least resembles the FerGes is merely due to a de- ficient knowledge of its coasts.
As regards SW. Iceland—Finmark the percentage of species common to both places is 56 and that of not common 44. Thus, the resemblance is somewhat less than that between Iceland and Finmark.
If we now turn to E. Iceland we obtain the following figures: —
common not common E. Iceland—West Greenland...... 58 °/o 42 %/o E. Iceland—East Greenland...... 53 %7/o A7%/o PE fecland—-White Sea... .4 <n. 39 %/o 61 °/o
E. Iceland has thus the greatest floristic resemblance to West Greenland, resembles East Greenland somewhat less and the White Sea least of all, although the floral districts of E. Iceland and the White Sea resemble each other most closely when the species are grouped according to geographical distribution (see above).
V. THE VERTICAL DISTRIBUTION OF THE SPECIES.
[' we walk along the beach at low-tide we see a belt laid bare, the breadth of which varies according to the degrees of declivity of the coast and according to the tides — that is according to whether it is spring-tide or neap-tide. At spring-tide the belt is broad and at neap-tide narrow. The low-water mark of neap-tide divides the belt laid bare into two parts, an upper part which is laid bare during every low-tide and a lower part which is laid bare only at and about spring-tide. The upper part, between the upper limit of growth of the algal vegetation and the low-water mark of neap-tide, which almost coincides with the lower edge of the Fucacee- belt, I call the Upper Littoral Zone. The lower part, from the lower edge of the Fucacee-belt to the usual’ low-water mark of spring-tide, I call the Lower Littoral Zone. Below low-water mark of spring-tide begins the vegetation which is constantly submerged. That the vegetation of the lower littoral zone is closely connected with that in the upper part of the constantly-submerged zone is natural and will be discussed subsequently.
In the following table a dash (—) denotes a habitat (depth) in which the species has been found many times, and a dot (-) one in which it has been found either once or comparatively rarely.
Table 7. The Vertical Distribution of the Species.
Litto-| ral Depth (metre)
zone
46—50
51-55
36—40 41—45 61—65
56—60
| | | | Rhodophycee. | | |
| Bangia fuscopurpureal?. (a1. 0.0.7 4 |
sl: Porphyrayimimiataly ce eee [===
1 No notice is taken of the extraordinarily low ebb-tides which occasionally occur and by which large Laminari@ are often exposed.
H. JONSSON: MARINE ALGAL VEGETATION 81 Table 7. The Vertical Distribution of the Species (continued).
Litto-| ral | samy Depth (metre) sl a] o/2/2|s/4| 2/2) 3/3] 2/3] 2/ 4/2 Mere Sr Ghul We Ile siai Ct i tP Lala Clb et las BS) 2) “)o) a S\a|&[a) 3] 3/S)5/ 8) 5/8
Eeeerpliiyra umbilicalis............. Se-OLpiynropsis coccinda............ Sme@omemocelis rosea... 2... ew eee s] Chantransia microscopica ........ (Ch. 2 IS 03 2 Se SMO MSCOUMCALA. ws sale ne ce cw ad ee 3°. Cy. WLNE2CI Ee a eae SEOnoOnGruUsS CrISPUS.......66.....:. s] Gigartina mamillosa ............. sleauimtielita’ plicata..........0...... s Phyllophora Brodizi v. interrupta. Sheemmenuoranifolia.... 2.6.62 5 26 ey ee s Actinococcus subcutaneus......... seCerarocolax Hartzil....0........... sl Cystoclonium purpurascens....... Smlummerciia Pennyl ......:5..666-% SM mrMOray ChmStata... 6. s Rhodophyllis dichotoma.......... sl] Rhodymenia palmata............ s Lomentaria clavellosa....... ue 3 Ly: IRD SS2) Hee Skene al eee SeEIGeamium COCCINCUM™....:....... s] Halosaccion ramentaceum........ smelesseria aldta. 5.00... c ee vce Webaernt corymbosa... 0.2. 6665. SaOeStIuOSa.....:.:. SMS AUGUIITCA .) 0052 c cel we os eee Bonnemaisonia asparagoides...... s Polysiphonia urceolata........... | IP, UES ESE 102 en ee ee GS [P, SUAS ICES ame SIBEPPIIPIEESCEDS als. epee coke oe hess s Pterosiphonia parasitica......... : s] Rhodomela lycopodioides......... SmOdeanenalia dentata 0.5.6. 0..0 0% s] Callithamnion Arbuscula......... SUCMSCOMMNGORUIN 2.2. 2 eee ee ols ee Seeluimanria elegans ...-.. 0. 6s. iced es SAMO UA DIUIMOSA ... ec eles so els SUPE OLIMACA Ss Ge ae oe Se sie ele os s Antithamnion Plumula v. boreale. SIMAPIOCCOSUIM ets cs be es efels wee we sl] Ceramium Deslongchampii .......
The Botany of Iceland. I.
82 H. JONSSON
Table 7. The Vertical Distribution of the Species (continued).
Litto- ral Depth (metre) zone i 51 siio| 2|3| 8/8131 3] 9/3) S) ee idee Per ent) Tl al at Te) Et) a BSI" oS A Sa Re eS) S)/ 5/8) s/s Peelers" ee s] Ceramium fruticulosum.......... | || / | Loti SG 2clrCInAcU |.) ols. se ee 4 2 See ea | PS aa | SUIG@zanbORescens © 50.0.0 aout ac | | SiC satlantiquimys J. waters weer + -] ¢| eon | | Si Gaqubnunas. 2g 2ise oss ge ty Sele ae . sl. acanthonotum- 25.60 400 souk. | | 1 Rhodochorton Rothii............. -l oo. | SANT repens. 6" atnteces teh eos en | “ leet | | SRGminutumn. 2 Soe e oe ere - | | sane penicilliformeys jay gee see eee sll gE Al acne SMe sR. membranaceumy: oF fs0.56. ps 33 a4 “| - - sili | sl Dumontia filiformis: 2... .2.02. <. a5 eS | | sliDilsea ‘edulis. sete soars. kc eee = | | | s ‘Petrocelis Hennedyi. 22.5229... |= | | s Crupmagarcticae sth. Aare eee - | elie / SIG: elite sa.) Wate ahd, ig cul ak ae I Rea | s Peyssonellia Rosenvingii.......... | -|—|—] +] - | s Rhododermis parasitica .......... | etl cele : s Lithothamnion glaciale........... (at | |. >| <1 Sas Sula. Umsertiy. {eee ei). Sn tees aee | of lo ; S MLS POP TTORin Gree en ok a ctee es | -|°] *|— t= 2) 2 S SLOHAVeESCeNS. Ferre ater ce aol eno aiece | 1° | cghechl Sela SE. Teecimad wim Aetna oe ee ! Sa fey? & AL eB Ves! aes C ipiaee S AA ei ha a <2 °5) aie : s LL Lenormandis. 3. foo ieee sal |. | sl Phymatolithon polymorphum..... we ae | | s Clathromorphum compactum..... | SS -| : s ‘Lithophyllaum Grouani . 22.2... 2 | |. s Dermatolithon macrocarpum ..... | IL = SS siCorallina somieinalis (7 0) we ee = 1 Hildenbrandta moses a7. be == Phzophycee. | s Lithoderma fatiscens............. = SS = 1 Petroderma maculiforme ......... | s. Ralistaovata."...45 5) ce wera eee 1) Ba yelawallaak. c10 2 ca) 2 cree ian ee eee = | | | 1 Ry Vermueasal. 20. 2 Sen eee ee ee ae sl Rs demstar css se ntt, 6 ea sero ee — | | 7 | sl Myrionema vulgare .............. | / || s* Mi) (Gorumie* 22h See. ea eee ee | | | s] M. globosum.: 30s. ae |: —| | | | | sk M, ferGense x.).ecaou asks Sec eee | |
MARINE ALGAL VEGETATION
Table 7. The Vertical Distribution of the Species (continued).
83
Depth (metre)
6—10 Wl 15
1—5 21—25
26—30
31—35 36 — 40
56—60 61— 65
66—70
sl Myrionema Laminariz........... Sewscoeyelus islandicus ..../........ sl Microsyphar Polysiphoniz........
s Streblonema ecidioides........... |
Sls. stilophore v. czespitosa......... tepeamelia: LtOralis) .... jo. 6. ce ees s Ectocarpus tomentosoides ........ PE TEOMPENLOSUS 4.6 ee ees SPE MEOMNERVOIMES).. kw ee eee SIPEISUMCMILOSUS! . Visa eee ee SPP EPBEMMUCINALUS 5. 6 ee ee ee ee SIE ICISENCUIAUUIS 9% es ee ede ROMMIINDEIS ICO eS ee ole ow eee
s] Leptonema fasciculatum v. subcy- ||
UDC TS G3\ ea Deeeors Peeiaenmista tucicola .........6.-6.. 1 Sphacelaria britannica ........ SUS) SEU G2 SMPMOMINGIGEAR ke he ee Sec m-ectopreris. plumosa ...........- s Omphalophyllum ulvaceum....... Seconeraria plantaginea............ sl] Litosiphon filiformis......... bs, A 1 Isthmoplea spherophora......... slsueuyasiphon tortilis.............. s] Pheostroma pustulosum ......... s] Scytosiphon Lomentaria.......... See bytes zosterifolia ............ S012. TES CIE) se ee Siu@otodesme: bulligera............. SEpictyosiphon Ekmani............ SU MesOsIGIAy a. ee nee 31D. OVC Pi ENG | ea SWMOPCOUVIMNOSUS 2... ae eee oes SiO SUP PUNOIdES. 1... ose ee eee SUDstoemiculaceus . 2.2... 66 ee eee se Se Mesimarestia ViTidis .... 006 sero RD MAGCTICALAS: 6 6 uy-s ee as eee eee es =, 1D. G1 a a siiCastagnea, VIrescenS .....:..5.+++>- slbbeatuesia difformis ........ +++. sl Chordaria flagelliformis ......-... s) Chords tomentosa ......0.....- +.
16—20
SS |
cS
84 H. JONSSON
Table 7. The Vertical Distribution of the Species (continued).
Chrordaicilim: anc ee See ed ct Saccorrhiza dermatodea ..........
I SeROCMSIS Es Af oe Ws oe Sie ee cows Li MIBTIPCS ee sks be awed ses ae aoe es Teclasubeita ss oy ard Macatawa gs ieiee rae Eeihiy perbOredsns his Ses ere ee ANAM ARE VA Cots Yale ew hecee aia os ot Ameseuleniter< Ak dusts the, sco-fersusee oe PUCUS Spirals 297 s0 cine Bie oe eee Ear habs Rae ae aus de eee ae ES a oe PONSCUEALUSES erent erie we es ee ae EP AVESICUIOSUS Ser. aos Sos ee ee Pelvetia, canaliculatal.. «220. 256... Ascophyllum nodosum...........
—— ie P OND nnn nA A
Chlorophycee.
1 Chlorochytrium Cohnii........... SCI CLUSUNET UNGER Oe sa yan oes
leg GeSelinaitianies foams 2-0 ee 2 “sl Codrolum Petrocelidisy: |... 2.2.5. PCyeresaniuin . csec etic cle eee PC sul lie os ee 3 ees pectic oe I -Percursarial pereursa 2. fu. ccs aes oe 1 Enteromorpha aureola ...........
TNA pe ttemte, os a eG Sa wie x
1 ] DAS Clacton ete, eee e Soe. whats 1 Monostroma groenlandicum ...... slMMGrevillleim ah vik
ly Prasiola*potyrrhizal erence back PSR tuniuracea..) S42 ie eee ee 1 (PSstipitatats i525 Shoat Ore ees a 1 Ulothrix consociata v. islandica... l Ussubilaccidas ojo OR eee oe lU. pseudoflaccassac..c. Seen ] AU, Hee ear ee ae on a heh Ge 1 Pseudendoclonium submarinum... sl Entoderma Wittrockii: ... 2.22...
Laminaria saccharina .:........::
!
Litto- ral Depth (metre) zone tel sy ol si el elel slo! s!e|elel/sle DO) Oo] Sim] al | op oo | | atl | us| S] | | Berti Ti Ti tl tl alt] 1) et ite eee O}] = wt Of] mt Om] OY] me] Ol | OO] I 3/ = Sha a] NI AN oo) oo] | S| |! wo] wo] SS { |
|
| eae ie
i)
MARINE ALGAL VEGETATION 85
Table 7. The Vertical Distribution of the Species (continued).
Litto- || | ral Depth (metre)
! |
6—10
11—15 16—20 21—25 26—30 31—35
| 36—40 41—45 |
| 46-50
| 51—55. 56 — 60 61—65. 66—70
88
be 5) Q Q =|
beaekochzete parasitica,............. ! | : o) 2. PE OS 2 ||? s] Bolbocoleon piliferum............ -|— feWiveliafucicola. ..... 22.0002. al shPrmegsheimia: scutata..0/2........ Memlaclieete. TETOXP. 6. fat oe oe viele» Mewmespora mirabilis... 0... ......... — : | iUle [5/21 1/211 ale rh or ae — | Sue wWormskioldit .:. 2. ).6 0.0.20 0% —||- 1 Chetomorpha tortuosum......... oss ; | Phe MMelarOMiUM':.......). 0%. s00+0 —|—|— 1] Rhizoclonium riparium.......... Ses s] Spongomorpha vernalis........... | j— 1 Acrosiphonia albescens........... = Sh LI CUDA 2 eS ae —| - SPM NUS EINE: oak ele ci os a wis seie cle wes es —|—|— PeemANeWIIOFINIS. -. 3... soe yoo IeAeepeMICMUTOVIMIS ....5........-65% le@ladophora Trupestris..:.:..... 2.10. oss Cartas oy, os Le. ecco Part aie ahs
1 (Cr, Sr (CCE a — l
]
S
S
WAAPANECSRENIS 7. oo io ols et ss Ay RITES ae aa Oe Beem
Gomontia polyrrhiza ............. Ostreobium, Oueketti.’.. 0-4... .6... |
Cyanophycee. Pleurocapsa amethystea.......... = Plectonema norvegicum.......... il Phormidium autumnale.......... . ) Spinmina, subsalsa ... 2... 2... +--> Calothrix scopulorum............ — IM VUNlARIA ALTA SoS. ee. oes
ee ee ee)
Fungi.
Dothidella Laminariz.........%.-.-- — | — | |
A. Upper Littoral Zone. The preceding table shows that 18 species of Rhodophycee, 18 species of Phwophycee, 36 species of Chlorophycee and 6 species of Cyanophycee grow in the upper littoral zone; that is, 78 species
86 H. JONSSON
in all. Of these species some are common and others rare; some are found exclusively in the upper littoral zone and others extend further downwards. In order to show this more distinctly, each group will here be dealt with separately and in detail.
Rhodophycee. Of the 18 species mentioned 5 are common, and the remaining 13 rarer. The following are the commonly dis- tributed species: Bangia fuscopurpurea, which is found exclusively in the upper littoral zone; Porphyra umbilicalis which is found also in the lower littoral zone; Polysiphonia fastigiata which occurs ex- clusively on Ascophyllum nodosum in the upper littoral zone; Rho- dochorton Rothit which extends to a depth of 10 metres, and Hilden- brandia rosea which extends to a depth of 5 metres. The three first-named species are common in places exposed to the light in the littoral zone; Rhodochorton and Hildenbrandia, on the other — hand, occur most frequently as an undergrowth, or in shady clefts (Rhodochorton), and at the bottom of pools (Hildenbrandia). These two species are met with more rarely in places exposed to the light. The 13 species which occur in the upper littoral zone, but which must be called somewhat rare, are there shade-loving, and are then found either as an undergrowth or in shady clefts and depressions. Some are epiphytes, and are then protected against de- siccation by the host-plant. The greater number of these 13 species are common in the lower littoral zone, and the 3 Ceramium-species which are recorded exclusively from the upper littoral zone may doubtless be expected to occur also in the lower littoral zone. Conchocelis does not occur in the lower littoral zone but is found at a depth of 6—35 metres.
Pheophycee. Of brown alge the Fucacee play the most important réle. The species are few in number, but are of social growth, and occur in such quantities that they comprise by far the greater portion of the bulk of the plants in the upper littoral zone. Of the 18 species mentioned above, 12 are commonly distributed, and 6 are more rare, in the upper littoral zone. Of the 12 common species, 9 are found exclusively in the upper littoral zone, viz., 6 species of Fucacew, Sphacelaria britannica, Ectocarpus tomentosus and Ralfsia clavata; Pylaiella littoralis, Elachista fucicola and Isth- moplea, on the other hand, range to a depth of about 10 metres. Of the rarer species, Petroderma is found exclusively in the upper littoral zone, Ralfsia verrucosa is most frequent in the upper littoral zone, but is also met with in the lower littoral zone, as an epi-
MARINE ALGAL VEGETATION 87
phyte; the remaining 4 species are common in the lower littoral zone, and occur in pools in the upper littoral zone, consequently they cannot, strictly speaking, be reckoned as belonging to the upper littoral zone.
Chlorophycee. In the table, 36 species of green alge are mentioned from the upper littoral zone. Of these, 15 are charac- terized as common and 21 as rarer. 31 species are recorded ex- clusively from the upper littoral zone; 2 species, Entoderma and Bolbocoleon are more frequent in the lower littoral zone; one species Chlorochytrium dermatocolax is as frequent in the lower littoral zone as in the upper littoral zone, one species Ulothrix flacca, which must be considered a decidedly littoral species, grows to a depth of about 10 metres. Ulvella fucicola also grows to a depth of 5 metres, but must nevertheless be considered littoral. In addition to these 36 species, others may be found in the upper littoral zone, which have a more downward extension (e. g. Monostroma Grevillei var. arctica, M. fuscum, Acrosiphonia incurva, and others), but they generally keep to the pools.
Cyanophycee. All the species hitherto found (6) grow in the upper littoral zone.
The species which are recorded from the upper littoral zone may be put into two divisions. The one comprises the species which are common in the upper littoral zone and are adapted to growth in places exposed to the light and the wind during the period of exposure; these species, then, might be termed strictly littoral. The other division comprises species which are common in the lower littoral zone or extend even further downwards. The greater number of these species does not occur in the open littoral zone, but is found as an undergrowth or in shady clefts, or in pools. The real home of these species is lower down than in the upper littoral zone, and for this reason they can scarcely be de- signated littoral species.
According to the above, there are in all 58 strictly littoral species: Rhodophycee 5 species, Pheeophycee 14 species, Chlorophycee 33 species and Cyanophycee 6 species.
The upper littoral zone is thus essentially characterized by a paucity of species of red alge, by many species of green algz and by a preponderance of Fucacee. The number of the species of brown alge is of less importance; it is three times as large as that of the red alge and about half as large as that of the green alge.
88 H. JONSSON
If we reckon, in percentages, the number of species of each group of the total number of species in the upper littoral zone we obtain the following figures. The strictly littoral species (58 in all) are indicated by a, the other species (20 in all) not strictly littoral are indicated by b, but no attention is paid to those species which may be found in the upper littoral zone and appear to grow by preference in pools.
Rhodophyceze Phzeophycece Chlorophyceze Cyanophycez aE PORES RED STEMS SR 5 (9%o) 14 (24 %/o) 33 (Tle) aa
UW ah ey avy SEE EME ltr 18 (23 °/o) 18 (23 %0) 36: (46-°/o), VOCS ia)
So far as the abundance of species is concerned I lay special stress on the red alge, green algz and blue-green alge. It would be confusing, especially as regards the red alge, to reckon the b- species as strictly littoral, nor can this be done, because they are not adapted for life in the open littoral zone. As regards the brown and green algze, on the other hand, it is of no essential importance whether the b-species are included or not, as they are so few in number.
If we calculate how great a proportion the strictly littoral species form of the combined number of each group we obtain the following figures: —
Rhodophyceze Phzeophycece Chlorophycee Cyanophycez Species known at pre- sent from Iceland.. 76 67 a1 6 Strictly littoral species 5 (6.6 °/o) 14 (20.9 °/o) 33 (64.7 °/o) 6 (100 °/o) a+ b (see above).... 18 (23.7 °/o) 18 (26.8 °/o) 36 (70.6 °/o) 6 (100 °/o)
B. The Lower Littoral Zone and the Belt below down to a depth of about 10 metres.
1. The Lower Littoral Zone. From this are recorded 93 species in all (Table 7), viz. 39 Rhodophycee, 37 Pheophycee and 17 Chlorophycee. Of these 93 species, the upper and lower littoral zones have 15 species in common (8 red, 5 brown, 2 green) which do not extend further downwards; the greater number of these belong, strictly speaking, to the lower littoral zone, as, in the upper littoral zone, they usually occur in pools or very shady spots. 19 species (8 red, 11 brown) have been found only in the lower littoral zone; but the majority of them probably occur also below the limit of low-tide, and, in any case, some have their area of distribution
MARINE ALGAL VEGETATION 89
close to this limit; 6 species (1 red, 3 brown, 2 green) have their area of distribution in the upper and lower littoral zones, and to a depth of 10 metres, these species are mentioned under the Upper Littoral Zone, and there, 5 of them are reckoned as littoral. 35 species (10 red, 15 brown, 10 green) grow in the lower littoral zone, and to a depth of about 10 metres. They appear to be about as common in the lower littoral zone as in the belt between the limit of low-tide and the depth mentioned. 18 species (12 red, 3 brown, 3 green) grow in the lower littoral zone, and to a depth of more than 10 metres; these belong to the species which have a lower downward range, 15 of them have their uppermost limit in the lower littoral zone, and 3 of them in the upper littoral zone.
The species characteristic of the lower littoral zone are especially the 19 species which are found there only, and the 35 species which extend to a depth of about 10 metres, for some of these (e. g. Rhodymenia and Halosaccion), by occurring in masses, often cha- racterize large portions of the lower littoral zone.
_ 2. The Belt down to a depth of about 10 metres. In the table 103 species are recorded from this belt. Of these, two occur also in the upper littoral zone, and have been previously mentioned (Rhodochorton Rothii and Hildenbrandia), 6 occur also in the upper and lower littoral zones and are mentioned above, 35 occur also in the lower littoral zone (see under this heading); while 9 species are found only at this depth, but of these some mav be presumed to extend further downwards and some may possibly occur in the lower littoral zone. 19 species extend down- wards, with their uppermost limit in the upper and lower littoral zones, as, for example, Conchocelis rosea which occurs in the upper littoral zone and is absent from the lower littoral zone, besides the 18 species mentioned under the Lower Littoral Zone. 32 species with a downward range have their uppermost limit at a depth of about 10 metres. :
Besides the 9 species which are found only in this belt, it is especially the 35 species which this belt has in common with the lower littoral zone which characterize the belt, as some of them — those mentioned under the Lower Littoral Zone — by occurring in masses often characterize large portions of the bottom.
By comparison it can easily be seen that the lower littoral zone is much more closely related to this belt than to the upper littoral zone, which, amongst other things, is evident from the great
90 H. JONSSON
number of red alge in the lower littoral zone. This can be dis- tinctly seen from the following figures: —
Upper Littoral Zone Lower Littoral Zone 58 species (a) 93 species. not common common not common Dl (39.427 /o) 7 (4.86 °/o) 86 (59.72 °/o) Upper Littoral Zone - Lower Littoral Zone 78 species (a + 5) 93 species not common common not common 54 (36.73 °/o) DANI. 33 9/0) 69 (46.94 °/o) Lower Littoral Zone From the limit of low-tide to a 93 species depth of about 10 m. 103 species. not common common not common 34 (24.82 °/o) 59 (43.06 °/o) 44 (32.12 °/o)
The figures show that the upper littoral zone is very unlike the lower littoral zone, especially if only the species which are characteristic of the latter, or which occur in the open littoral zone (a), are taken into consideration, which is most correct, as the shade-loving species in the upper littoral zone must be regarded as stragglers from associations lower down. As previously mentioned, the lower littoral zone bears the greatest resemblance to the belt which exists lower down (to a depth of about 10 metres).
The species which have their lower limit of growth at a depth of about 10 metres and which are commonly distributed in the lower littoral zone I designate semi-littoral because they are found both laid bare during low-tide in the lower littoral: zone and con- stantly submerged in the belt below; as these species especially characterize the lower littoral zone and the belt below to a depth of about 10 metres I designate this area the semi-littoral zone. It must not be concluded, however, that semi-littoral vegetation covers the bottom everywhere down to a depth of 10 metres; below the limit of low-tide the semi-littoral vegetation appears rather to consist of stragglers from the lower littoral zone into the Laminaria-belt. Thus the semi-littoral zone is situated between the Fucus-belt and the La- minaria-belt. The species which specially occur in the semi-littoral zone I designate on the whole as semi-littoral, also those which are found in the lower littoral zone and are not found below the limit of low-tide; they will probably be found also below this limit. Species which are common in the lower littoral zone and are rare in the
MARINE ALGAL VEGETATION 91
upper littoral zone, but not known below the limit of low-tide I have also designated semi-littoral as they might be expected to grow lower down.!
C. The Sublittoral Species.
These species play the principal réle in the sublittoral vegeta- tion. This may be characterized in a somewhat similar manner as the vegetation of the upper littoral zone, although conversely as regards red and green alg, viz. by a large number of red alge and an extremely small number of green alge and by the occur- rence of a mass of Laminariacew. In Table 7, these species are marked with an s before the name. Their number is shown by the following figures: —
Species Littoral Semi-littoral Sublittoral Week) bbw as Sar 5 30 39 ISOs i Lt Sh rr 14 31 22 SE EID eee aa cae ar ae 1 3 iie-STeEM 2). oie) )s 2 6 d 6) 7 58 76 64
From a comparison of the number of species of the sublittoral zone with that of the littoral and semi-littoral zones it is seen that it is smallest in the littoral zone, somewhat larger in the sublittoral zone and considerably larger in the semi-littoral zone. Species of green algze occur most abundantly in the littoral zone, and their number is infinitesimal in the sublittoral zone. Red alge are most numerous in the sublittoral zone and very scarce in the littoral zone. The brown algz are more evenly distributed in the different zones, yet they are richest in species in the semi-littoral zone. The blue-green algz are found exclusively in the littoral zone.
In the semi-littoral zone the large brown alge do not occur in masses like, for example, the belt of Fucus in the upper littoral
1 As regards the majority of the species (see Table 7) it is easy to decide whether they are littoral, semi-littoral or sublittoral, but there are some species, nevertheless, which it is difficult to refer definitely to any one of the three zones mentioned, and therefore it is sometimes a matter of opinion whether they should be reckoned in the one or the other. By perusing the table these species are easily detected.
2 Two species, Delesseria Baerii and Bonnemaisonia asparagoides are not in- cluded as their habitat is unknown to me (see 31, pp. 140, 141).
92 H. JONSSON
zone and the belt of Laminaria in the sublittoral zone. This is possibly the reason why the semi-littoral zone is richest in species.
In Table 7, 64 species are recorded as sublittoral. Besides these, semi-littoral species occur in this zone, especially as epiphytes, or, more rarely, as undergrowth. 12 species, almost all semi-littoral, which extend to a greater depth than 10 metres are mentioned in the table. In addition, about 14 species can be regarded as epi- phytic, particularly in the upper part of the sublittoral zone. The sublittoral vegetation is thus composed of 64 sublittoral species and of about 26 semi-littoral species, or about 90 species in all.
Lower Limits of Growth.
As far as the lower limit of growth is concerned the species which are found below low-tide must be dealt with collectively. In the following table, which shows the lower limits of growth, all the depths at which species have been known to occur have been, as a rule, taken into consideration, and thus the table does not indicate the depth of their general distribution or the depth at which they form associations (see under Vegetation). In the table, 2 red alge are omitted, as I have no further knowledge regarding their habitats (31, pp. 140, 141). These species are Delesseria Baerti and Bonnemaisonia asparagoides. As regards the green alge it must also be stated that I have not taken into consideration the records from greater depths than 10 metres. I myself am responsible for some of these records; the alge often were detached, but sometimes it appeared as if they really had been growing at the depth recorded. I always, however, have entertained some doubt concerning this, and consequently prefer at present not to consider records from such depths. Regarding Chlorochytrium inclusum the record is cor- rect, as it grew in Turnerella, which was attached to the bottom at a depth of 30 metres. For Gomontia and Ostreobium I have given the most common depth, down to about 40 metres, but I have also obtained these species, growing inside an old shell of Mya, from a depth of about 60 metres.
It should be further stated that I do not know the depth to be given for Desmarestia ligulata. This species has been found by Ove Paulsen between the Vestmannaeyjar and South-Iceland; I presume that it grew at a depth of about 20 metres.
MARINE ALGAL VEGETATION 93
Lower Limits of Growth in metres (see Table 7).
About 5—10 About 15-20 About 25-30 About 35—45 About 60 mearalige ...... 13 10 10 15 ii Brown alge.... r9 8 4 4) 3 Green algz..... 16 ae 1 2 Total... 48 18 15 22 10
37
In the above table 113 species are mentioned, of which 48 do not extend to a greater depth than about 10 metres, 18 extend to about 20 metres, 15 to about 30 metres, 22 to about 40 metres and 10 to about 60 metres and more. Thus there appears to be a flori- stic boundary at a depth of about 10 metres; while another boundary can be faintly distinguished at a depth of from about 30 to 40 metres, as there are 37 species which appear not to extend further downwards; and here, also, is situated the lower limit of growth of most of the Laminariacee which play the same role on the sub- littoral bottom as the Fucacee play in the littoral zone. Exactly where the lower limit of growth, as regards the marine alge in Iceland, is situated — whether it lies at a depth of about 60 to 80 metres or deeper — I cannot at present decide, but it is most pro- bable that the vegetation at greater depths than 60 metres is, in any case, extremely poor in species.
According to the above statements the lower limits of the algz are as follows: —
The littoral limit (Upper Littoral Zone) ......... 53 species 26.77 °/o erat tr Hl. LOW-E... 6 = vaso ¢ oon cs oo c.e ne oe os abe a teem 0 mmepeurel metres... 2). 2). SPS. PSS Me SP DAO Ty Ampamt 20; mmmetresii. <h. 2k. fea pal ons LS eoe= 9.09 °/o At about 30—about 40 metres................. 37 — 18.68 °/o freabout 60. metres and. more... ... 2.08 os. 10 — 5.05 °/o
198 species.
By future investigations all these figures will undoubtedly be altered and many of them to no inconsiderable extent; but the four principal boundaries, namely the littoral limit, the 10-metre limit, the 30—40 metre limit and the absolute depth-limit will always remain evident.
As regards the absolute depth-limit I cannot make any definite statement. The dredgings which I myself have undertaken have all been conducted with a small dredge from a small rowing boat.
94 H. JONSSON: MARINE ALGAL VEGETATION
The positive results which are obtained with this small dredge are satisfactory enough when the material is inspected with sufficient criticism, but it should not be concluded with certainty from a negative result (that is, when absolutely nothing comes up from the bottom) that no plants grow there. In great depths, also, dredging is difficult from a small rowing-boat. In some places only, in SW. Iceland and E. Iceland, have I undertaken dredgings in a depth of about 80 metres, and the result has been negative. In those places where the plummet revealed a clayey bottom, it was certain that no plants were growing there. Off S. and SW. Iceland I have met with no vegetation at a greater depth than about 40 metres, but in Reydarfjoréur in E. Iceland, on the other hand, I have come across plants at as great a depth as about 60 metres. This might indicate that the vegetation extends further downwards in E. Iceland; but as the observations are too few, this point must remain undecided until further investigations are forthcoming.
It was a fairly common occurrence, especially in the fjords of E. Iceland, to encounter sunken fragments of algz (often strictly littoral species) and of mosses in depths of more than 22 metres. In Seydisfjéréur I came across leaves of Betula and Salix at a depth of 14—20 metres.
C. H. Ostenfeld (the Ingolf Expedition) found Lithothamnion laeve in great quantities at a depth of 88 metres off the north coast of Iceland, and R. Hérring (on board the “Diana,” off E. Iceland) found Lithothamnion tophiforme at a depth of 70 metres. In depths of from 60 to about 100 metres Hoérring found, in addition, frag- ments of various algz, amongst which were strictly littoral species, and of mosses which had evidently fallen to the bottom. In order to draw the attention of future investigators to this matter it must further be mentioned that Hérring brought home in spirits a young plant of Laminaria saccharina from a depth of from 81 to 104 metres (Mjoifjérdur, 14.5.1898, St. XIII) and on the label was written “In the trawl were many large Laminarie which had been torn away from the bottom.” The Laminaria brought home appeared normal, and, if it had fallen to the bottom could only have lain there for a short time. What is most likely is that the trawl passed over an uneven bottom, and that the Laminari@w grew at a lesser depth than that mentioned; or is it possible that the deep-water form of Laminaria saccharina ranges so far downwards? I leave it to future investigation to decide this question.
VI. MARINE ALGAL VEGETATION AND SEA- GRASS VEGETATION. |
6 aa vegetation of the sea is naturally divided into two principal groups: the Plankton composed of the small plants floating passively in the water, and the Benthos which comprises the species attached to a substratum. In this article only the latter is dealt with.
The Benthos?* falls naturally into two divisions, viz. the litho- philous vegetation, the communities of marine alge (subformation of marine alge, Halo-nereid communities, Warming, 72, p. 170), and the vegetation of loose soil (Enhalid-formation, Warming, fa. pe177).
The Benthos has been divided in different ways. J.G. Agardh in 1836 (Novitiz Flore Sveciz) divided the marine vegetation into three zones, a green zone above, a brown zone in the middle and a red zone lowest of all. Lyngbye in the same year, also divided the vegetation into three zones (Rariora Codana, printed 1879—80), a zone of green alge (Ulvacew) being above, a zone of red alge in the middle and a zone of Laminariew below this. Orsted (77), like Agardh, also divided the vegetation in the Oresund into three zones, but @rsted has the merit of being the first to explain that the division of the zones depends upon the depth to which the light penetrates, and upon the colour of the light at the various depths.
Kjellman has divided the algal Benthos into regions. Where there is a tide, the littoral region is reckoned as being between the highest high-water mark and the lowest ebb-tide mark; where, on the other hand, there is no tide Kjellman reckons the littoral region as extending from the uppermost limit of the algal vegetation to a depth of 11/2—2 fathoms (34, p.7). The sublittoral region ex- tends from the lower limit of low-tide, or else from a depth of 1'/2
1 No notice is taken of the bacterial flora of the sea.
96 H. JONSSON
—2 fathoms, down to a depth of 20 fathoms; and finally the elittoral region stretches from the 20-fathom contour downwards. This division, unchanged in its main features, is generally employed. The boundary between the littoral and sublittoral regions is, I think, commonly supposed to be rather sharply defined in places with tides, and less sharply defined where tides do not occur.
By this division into three regions the algal Benthos is divided into three belts of different depth. Although the boundary lines thus drawn may be described as floristic boundaries, as regards many species, yet they cannot always be regarded as natural limits of vegetation. If natural limits of vegetation are to be drawn, several factors must be taken into consideration. From depth-records, pure and simple, a somewhat clear idea may naturally be formed of the conditions of light, but not of the salinity and warmth. If the conditions of light, salinity and warmth in those layers of water where the algal vegetation lives were known all the year round it would be easy to characterize the limits of the vegetation. The great importance of the salinity to algal vegetation is well-known and is emphasized by Rosenvinge (63), Svedelius (71), Bérge- sen (12) and Kylin (45), amongst others.
The ecological factors in the coastal waters round Iceland are not so well known that I am able to draw the natural limits of the vegetation by means of them. My starting point is, therefore, the vegetation itself, and from the appearance of the vegetation it is possible, to a certain extent, to form an opinion as regards the ecological factors, in the same way as an opinion may be formed from these concerning the appearance and composition of the vegetation.
The marine algal vegetation divides itself into several zones as the Benthos does in fresh water. The divisions between the zones in the sea are very distinct: some species seem to be spot-bound or very sensitive to changes of level; other species may occur in two or several zones; but it depends especially, I think, on the quality of the water, the intensity of the light and, where there are tides, on the period of exposure (in the littoral zone).
By studying the vertical distribution of the species and asso- ciations, I have come to the conclusion that the marine algal vege- tation may be divided into three zones almost parallel one with an- other: the Littoral Zone, the Semi-littoral Zone and the Sublittoral Zone.
The Littoral Zone understood in a more restricted sense is identical with the upper littoral zone and extends almost to the
MARINE ALGAL VEGETATION 97
low-water mark of neap-tide, and is exposed during each low- tide; the upper littoral zone is, then, the littoral zone proper, which doubtless corresponds exactly with Kolderup Rosenvinge’s limitation of the littoral zone in Greenland, but not entirely with Boérgesen’s limitation of the littoral zone in the Fer6ées, as some of the Feerdese littoral associations seem to belong to the next belt.
The semi-littoral zone extends from about the low-water mark of neap-tide to a depth of about 10 metres, and thus extends over the lower littoral zone, and even lower than that. In reality this zone comprises the lower littoral zone including stragglers below the low-water mark of spring-tide to a depth of 10 metres. That part of the zone lying in the lower littoral zone is laid bare at and about spring-tide, but is submerged at neap-tide.
The sublittoral zone extends from the low-water mark of spring- tide to the absolute depth-limit.
There seems to me to be no reason for calling any part of the Benthos elittoral. Even if the 40-metre contour is a lower limit of growth in the case of several species, and is, approximately, the lower boundary of the Laminaria-community, yet the upper bound- ary of the red-algze communities which extend further downwards than 40 metres lies much higher, and the 40-metre contour thus cuts straight through natural communities. It cannot, therefore, be considered the principal boundary as regards the whole of the constantly-submerged vegetation. Strémfelt (l.c.) is of the opinion that, possibly, elittoral vegetation does not exist on the coasts of Iceland. According to Kjellman the elittoral vegetation is extremely poor in species, and probably has a limited distribution everywhere in the northern seas. From what+has been said above respecting the 40-metre line, and from a comparison with Greenland (Rosen- vinge, 63) and the Ferées (Bérgesen, 11 and 12), it is obvious that a division of the constantly-submerged vegetation at this depth- line is not quite natural in the northern seas. It is more correct, therefore, to do as Rosenvinge and Boérgesen do, and to class the vegetation as sublittoral down to the absolute depth-limit.
In the following I do not employ the term “region,” which is now generally used to describe somewhat limited subdivisions of
The Botany of Iceland. I. 7
98 H. JONSSON
the vegetation, as I have thought it better to designate the algal