354 



Prasiola furfiiracea (Mert.) Menegh., Imhauser Prasiola p. 26G; Fosl. 

 Gonlrib. I, p. 127; Borgesen Faer. Alg. p. 48G. 



The Icelandic specimens occur on rocks at high-water mark often in 

 company with P. stipitata, they agree fully with the description given by 

 Imhauser (1. c.) and also with the Faeroese specimens (Borgesen 1. c). 



E. I eel. Vattarnes; Holmar. 

 N. I eel. Grimsey (0. D.). 

 SW. Icel." Reykjavik. 



Prasiola stipitata Suhr, Imhauser Prasiola p. 272; Kjellm. Arct. Alg. 

 p. 303. 



The species occurs on rocks and stones at high-water mark. It is 

 much more common and gregarious than the last named species and it 

 often covers the rocks with a green growth. Probably common. 



E, Icel. Vattarnes, Brimnes, Borgarnes. 

 N. Icel. Gri'msey (0. D.); EyjafjorOur. 

 NW. Icel. Skalholtsvik. 

 SW. Icel. Reykjavik. 

 S. Icel. Vestmannaeyjar. 



Fam. Ulotlincaceae. 



llothrix consociata Wille Studien p. 25. 

 var. islandica nov. var. 



I have in several places met with a Ulothrix, which in company with 

 other algse e. g. Ulothrix flacca, Codiolum and Urospora mirabilis forms 

 a matted growth on rocks at or above high-water mark. My specimens 



are all in dry condition 

 and their colour is light 

 green or light yellow- 

 green. The filaments are 

 not rarely adherent to 

 one another especially 

 in the lower part, and at 

 the base usually few or 

 many filaments coalesce. 

 The thickness of the fila- 

 ments varies from \0 jx 

 to 29 ^, but they are 

 usually 14 — 22// thick. 

 The length of the cells I have found varying from about Vs to ^/s of the 

 breadth, and I have only occasionally seen cells, which were as long as 

 broad. The cell-walls are usually very thick, especially the outer walls, 



a 



Fig. 5. Ulothrix consociata Wille var. islandica 

 nov. var. a, b, c (311 : 1) show the base of the fila- 

 ments with the rhizoids (compare the text); 

 cl C^IS : 1) shows three filaments, which coalesce 

 at the base. 



