The Marine Al^ae of Iceland. 



(11. Phaeophyceae.) 



By 

 Helgi Jonsson. 



Phaeophyceae. 



Fani. Myrionemaceae. 



Lithoderma fatiscens Aresch., emend. Kufkuck Bemerk. I, p. 238. 



This species is found on rocks, stones, shells and on other alga^. 

 It belongs to the sublitoral region and has been found down to a depth 

 of 12 fathoms, but 1 have also sometimes met with it in the lower litoral 

 region on stones or other algse. Once I have found it in a pool above 

 high-water mark, growing on Ghfetomorpha Melagonium, on a much ex- 

 posed coast, where only spray of the surf could reach it; the specimen 

 was well agreeing with the typical form, and had young unilocular spo- 

 rangia in July. 



My material of this species has been gathered in the spring- and 

 summer-months, and is for the most part sterile. I have only in June 

 and July met with some few plants having young unilocular sporangia. 



E. I eel. Vattarnes. 



N. I eel. Grjotnes (CO.): EyjafjorOur. 



NW. Icel. Prestsbakki; IsafjorOur (CO.); DjrafjorOur (Ldbk.). 



SW. Icel. Melar, Stykkisholmur ; Keflavik by Sna?fellsjokull (CO.). 



Petroderma iiiaciiliforme (Wollny) Kuck. Bemerk. II, p. 382. 



The specimens I have referred to this species agree well with 

 Kuckuck's description (I.e.). The thickness of the filaments was 7 — 9//. 

 and the unilocular sporangia were 14/i long and 10/^ broad. As a rule 



Botanisk Tidsskrift. 25. Bind. 10 



