— 159 - 



a typica is the most common. 



ß lubrica (Rupr.) Rosenv. is rather common. 



Rosenvinge (1. c.) points out that these two varieties are connected 

 with intermediate forms in Greenland, and I have observed the same in 

 my material. 



The species is very common along the Icelandic coasts, and grows 

 both in the litoral region on other algæ e. g. Fucus versiculosus, F. inflatus 

 and Halosaccion ramentaceum, and in the upper sublitoral region on 

 Halosaccion. It has been gathered with unilocular sporangia in April — 

 Sept. A specimen was gathered by G. Ostenfeld amongst plankton in 

 64° N. Lat. and 23° 25' W. Long. 



Fam. Sphacelariaceæ. 



Sphacelaria britannica Sauvag. Sphacelaria p. 50. 



The basal portion of the frond of my specimens consists of more or 

 less irregularly formed cushions with marginal growth (Fig. 16, b). The 

 cushions are of varying size and 

 emit both erect filaments and hori- 

 zontally running stolons (Fig. 16, ft) 

 from which also erect filaments arise. 

 The largest part of the basal portion 

 is usually formed by the stolons. 

 In other respects my plants fully 

 agree with Sauvageau's description. 

 Most of my material is sterile, and 



I have only met with plants bear- c \ 7 . 7 ., . 0 



J r Fig. 16. bpfiacelaria britannica Sauv. 



ing unilocular sporangia in March at compare the text. (126 : 1.) 



Reykjavik. The species occurs in 



the upper litoral region, and in company with other algæ, e. g. Sphacelaria 

 radicans, Rhodochorton Rothii, Polysiphonia urceolata a. o., it forms a 

 widely expanded, matted growth frequently occurring as undervegetation in 

 the Fucus zone. 



NW. I c el. Rroddanes. 



SW. I cel. common. 



S. I c el. Vestmannaeyjar. 



Sphacelaria radicans Harv., Sauvag. Sphacelaria p. 27, fig. 14; Reinke, 

 Sphacelaria p. 8, Tab. Ill, fig. 1, Kuck., Bemerk. I, p. 229, fig. 4. 



The Icelandic specimens agree fully with Sauvageau's description (I.e.). 

 The length of the plant is about 1 cm., the erect filaments are 30 — 60^ 

 thick, the unilocular sporangia 50 — 60 fx long and nearly equally broad. 



11* 



