-144 M. Foslie. 



part of the sublitoral zone together with Arttithamnion floc- 

 cosum. The Finmarkian specimens are 10 — 12 [k thick, bea- 

 ring zoospores at East-Finmarken in the later half of July 

 and in the first part of August, at West-Finmarken in the 

 middle of June, and in Tromso amt at the beginning of June. 

 Distribution: Pretty common along the whole coast 

 and in several places rather plentiful. 



Ulothrixflacca (Dillw.) Thur. 



in Le Jol. Liste Alg. Cherb. p. 36 ; Conferva flacca Dillv. Brit. 

 Conf. t. 49. 

 Descr. Ulothrix flacca Hauck, Meeresalg. p. 442. 



„ „ Farl. New Engl. Alg. p. 45. 



Fig. Hormotrichuni flaccuni Ktitz. Tab. Phyc. 3, t. 63. 

 „ didynum Kiitz. 1. c. 



Ulothrix flacca Tab. nostr. 3, fig. 1 — 3. 

 Exsicc. Lyngbya Carmichaelii Wyatt, Alg. Danm. Nr. 230. 



Hormiscia flacca Areseb. Alg. Scand. exsicc. Nr. 342. 

 Syn. Lyngbya Carmichaelii Harv. Phyc. Brit, t. 186, A.; fide eit. 

 Urospoia penicilliformis Aresch Obs. Phyc. 2, p. 4; ex parte. 

 „ „ Kjellm. N. Ish. Algfl. p. 386; ex parte. 



Lyngbya flacca Harv. 1. c. t. 300. 



I agree with F a r 1 o w and Hauck considering the 

 present plant a pretty well differentiated species. Along 

 the coast of northern Norway at the least it is easely re- 

 cognized, except in a younger state, when it is difficult to 

 distinguish this species from young specimens of Urospora 

 penicilliformis. Sometimes two threads are grown together, 

 and now and then the plant bears very short, attenuated, 

 simple branches, which are thinner than their main axis. 

 The cells are often unequal in length in transverse direction 

 of the frond, and often also varying in shape, reminding of 

 certain forms of Schisogonium radicans. Cp. Kjellm. Spetsb. 

 Thall. 2, t. 5, fig. 10 — 11. Sometimes they are very short 

 in longitudinal direction of the frond, and the zoosporiferous 

 ones are varying rather much in shape even in the same 



