^™™ 



MARINE ALGAL VEGETATION 



163 



Pterosiphonia parasitica. To show how rich in species the epiphytic 

 vegetation occurring on a single individual of L. hyperborea may 

 be, the following species, also from the Vestmannaeyjar, may serve: 

 Desmarestia viridis, Ptilota plumosa, Delesseria sinuosa, Delesseria alata, 

 Lomentaria clavellosa, Polysiphonia urceolata, Plocamium coccineum, 

 Delesseria sanyuinea and Euthora cristata. 



So luxuriant and finely developed an epiphytic vegetation gives 

 to the Lamz'fian'aeea'-community of S. Iceland a character different 

 from that which it has in E. Iceland. 



On the stipes of Alaria and Laminaria digitata, on the other 

 hand, a similar epiphytic vegetation occurs in both the coastal 

 districts. 



The zonal division of the marine algal vegetation is in its 

 main features similar in E. Iceland and S. Iceland, as is shown by 

 the following examples which have been taken straight from the 

 diaries. 



East Iceland. 



Vattarnes, steep cliffs, 

 highly exposed. 14 /t. 

 I. Ulothricetum U. flaccae. 

 II. Bangietum B. fuscopurpurae. 



III. Porphyretum P. umbilicalis. 



IV. Fucetum F. inflati, in the most 

 exposed localities, consisting 

 only of f. exposita. 



V. Rhodymenietum. 



Halosaccionetum. 



Acrosiphonietum. 



VI. Sunlit. Alarietum. 



Borgarnes, sloping rocky coast, 

 considerably exposed. 13 /6. 

 I. Prasioletum P. stipitatae. 

 II. Ulothricetum U. flaccae, in great 

 abundance. 

 Rhizoclonium in crevices. 



III. Bangietum B. fuscopurpureae, 

 in wonderful abundance. 



IV. Porphyretum P. umbilicalis, of 

 great extent. 



V. Monostroma groenlandicum. 

 VI. Fucus vesiculosus, sparse and 



miserable. 

 VII. Fucetum F. inflati, abundantly. 

 The specimens very variable. 



VIII. Halosaccionetum H.ramentacei. 

 Urospora Wormskioldii. 

 Polysiphonia urceolata. 

 Rhodomela lycopodioides. 

 Chorda tomentosa. 

 IX. Alarietum. 



Holmanes, somewhat exposed, 

 sloping rocky coast. 18 /7. 



I. Ulothricetum U. flaccae. 



II. Enteromorphetum E. intesti- 

 nalis. 



III. Fucetum, uppermost, narrow 

 margin of F. vesiculosus, be- 

 low that, broad belt of F. in- 

 flatus, intermixed here and 

 there sparsely with Ascophyl- 

 lum nodosum. 



Under-veg. Hildenbrandietum. 



IV. Halosaccionetum, intermingled 

 with Monostroma fuscum, Por- 

 phyra miniata, Rhodymenia 

 palmata and a few Fucus in- 

 flatus. 



V. Alarietum, composed of Alaria 



esculenta and A. Pylaii. 

 VI. Laminarietum L. saccharinae. 

 VII. Laminarietum L. digitatae. 



11* 



