182 H. JONSSOX 



with abundance of new shoots. The Rhodgmenia^egetalio'n is never 

 really luxuriant in this place; it attains, however, to a greater 

 luxuriancy in spring and summer than during winter. Halosac- 

 cioneta occurred also here and there, but sparsely and not nearly 

 as abundantly as in spring and summer, but the same applies to 

 it, as to Rhodymenia, that it never grows really luxuriantly in this 

 place. There were noted in addition: Monostroma fuscum, Py- 

 laiella littoralis (extremely sparsely) and Enteromorpha intestinalis f. 

 prolifera, also extremely sparsely. Lithodermeta occurred abun- 

 dantly and were well -developed, but the species was sterile. A 

 Sphacelarietum composed of Sphacelaria radicans was found here 

 and there. The plants were low in growth, sterile and without hairs. 

 A Gigartinetum occurred here and there of about the usual extent. 



Just below the limit of low- tide I gathered the uppermost 

 stragglers from the sublittoral zone. There Laminaria saccharina, 

 L. digitata, L. hyperborea and Alaria esculenta f., were growing. All 

 the Laminarias were sterile and the new r laminae had not begun to 

 grow. The frond of the Alaria was usually torn in pieces; in the 

 middle of the stipe there were old sporophylls. The uppermost 

 part of the stipe, just below the leaf-base, was young and evidently 

 growing. Lowermost in the part that was growing, small projections 

 could be seen on the two sides, which were evidently the begin- 

 nings of new sporophylls. 



The following species were found thrown ashore: Lami- 

 naria saccharina, L. digitata, L. hyperborea, Alaria esculenta f., Sac- 

 corrhiza derrnatodea, Dcsmarestia aciileata, Odonthalia dentata, Petro- 

 celis Hennedyi richly fruiting (on L. hyperborea), Rhodochorton Rothii 

 (on L. hyperborea), Delesseria sanguinea with the small tetraspore- 

 bearing fronds, and Ptilota plumosa with tetraspores. 



For the further understanding of the winter-life of the algae it 

 may be mentioned that the winter of 1911- -1912 was unusually 

 mild at Reykjavik. 



