14,0, M. Foslie. 



spores have been collected in the later half of Jnne, in July 

 and August. At Tromso I have taken such ones in Octo- 

 ber (/. pannosa). 



Distribution: Common and pretty plentiful almost eve- 

 rywhere, at some places, for. inst. Mehavn, abundant (f. ty- 

 pica). The form valida is rather scarce, and f. pannosa has 

 not been found at East-Finmarken but at West-Finmarken 

 and in Tromso amt. 



Rhizoclonium rigidum Gobi 

 Algenfl. Weiss. Meer. p. 85. 

 Descr. Rhizoclonium rigidum Gobi, 1. c. 



Exsicc. Conferva fraeta f. longissima subsimplex Aresch. Alg. Scand. ex- 



sicc. Nr. 273. 

 Rhizoclonium rigidum Wittr. et Nordst. Alg. exsicc. Nr. 626. 

 Cfr. Conferva implexa Wyatt, Alg. Danm. Nr. 142. 

 Syn. Cladophora fraeta Kleen, Nordl. Alg. p. 45. 



This species is sometimes, especially in the state bea- 

 ring reproductive organs, somewhat cm led and twisted. I 

 have specimens collected at East-Finmarken which almost 

 fully correspond with Conferva implexa Wyatt, Alg. Danm. 

 JSTr. 142 even in thickness (25 — 36 \k). But the latter is by 

 L e Jolis in Liste Alg. Cherb. p. 58 referred to Bh. tortu- 

 osum. To my opinion it does not belong to the last named 

 species, being so nearly related to Bh. rigidum that no li- 

 mit hardly may be drawn between them, and I do not 

 think the two species may be united. Conferva tortuosa 

 Wyatt 1. c. Nr 190, which is a Bhizoclonmm, more re- 

 minds of Bh. tortuosum, but it is more slender than the 

 common form of this species. Bh. rigidum has in general, 

 as far a I have seen, a thickness of 18 — 25 pi. However the 

 specimens distributed by Areschoug 1. c. is coarser, 

 .about 25 — 35 p. thick. Bh. tortuosum is a smaller plant, 

 has a dark green colour, the threads are 30 — 45 p. (or, ac- 

 cording to Farlow, 35 — 58 p.) thick, and much curled an4 



