MARINE ALGAL VEGETATION' 181 



culosus, AscophyUum nodosum and Fucus in flatus). The vegetation 

 was as luxuriant during winter as in the other seasons of the year 

 when, however, the epiphyte-vegetation of the Fncus-belt is excepted. 

 For further information concerning the Fucacece see p. 173. Epi- 

 phytes, for instance such as Pylaiella littoralis and Elachista fucicola, 

 which at the other seasons of the year are common everywhere in 

 the Fzzcns-belt, were not observed. On the other hand, Polysiphonia 

 fastigiata occurred in abundance on Ascophyllum. Of intermixed 

 species in the Fjzchs -belt Cladophora rupestris may specially be 

 mentioned; it occurred abundantly as well-developed specimens with 

 the uppermost apex of the shoots destroyed. 



A Hildenbrandietum occurred everywhere in the littoral 

 zone, of similar appearance and extent as at the other seasons of 

 the year. 



In rock-crevices at the level of the Fucus-be\t a well-developed 

 Rhodochortonetum Rothii was found. The Rhodochorton was 

 sterile and Pleurocapsa amethystea was growing upon it. In such 

 crevices were noted in addition: — Pylaiella littoralis, sterile and 

 in very small quantity; Acrosiphonia sp. , a few filaments; Clado- 

 phora rupestris, abundant; Polysiphonia urceolata, sterile and with- 

 out hairs and sparse, and Callithamnion sp. 



The vegetation of the Pools was on the whole very poorly 

 developed. The upper pools, at the level of Peluetia and Fucus 

 spiralis, contained a few small individuals of Cladophora sericea f., 

 a few filaments of Pylaiella littoralis, a few small individuals of 

 Monostroma fuscum, and Diatoms in abundance. In such pools 

 Cladophora sericea forms a dense and luxuriant vegetation in spring 

 and summer. Fucus inflatus f. linearis grows also in these pools in 

 spring and summer, but was not found there in winter. It appears 

 as if this form is annual, at any rate in the upper pools. The 

 lower pools, almost at the level of the lower part of the Fucus- 

 belt, contained only a poor vegetation. Monostroma fuscum, how- 

 ever, occurred fairly abundantly, but Halosaccion ramentaceum was 

 found more sparsely; on Halosaccion was growing Elachista fucicola 

 v. lubrica with unilocular sporangia and somewhat sparse assimila- 

 tory filaments, and also Ceramium sp. 



Below the Fucus-belt, in the lower littoral zone (upper part 

 of the semilittoral belt) were found at Efferseyjargrandi, Rhody- 

 menieta distributed in patches here and there, many of them of 

 rather considerable size. The majority of the individuals were old, 



