Contribution. I. 



1^7 



fers from typical specimens chiefly by its darber colour, 

 greater rigidity, coarseness, shorter cells and thicker cell- 

 walls, but I haye seen almost every transition, and it ap- 

 pears to be so nearly related to tbe latter that it liardly 

 niay be regarded even a named form of the species. The 

 present plant is rather much variable. I have seen speci- 

 mens even still slenderthan that one distributed inWyatt, 

 Alg. Danm. 1. c, though the Finmarkian specimens appear, 

 in general, to be coarser than the British ones. 



The species in question islitoral, occurring in pools in 

 the lipper part of the region. It thrivesbest on open coast 

 but is also to be met with in sheltcred localities, attaining 

 a length of until 80 cm., and it is furnished with zoospores 

 in the later half of July and in August. 



Distrihtttion: Pretty common and at several places ra- 

 ther plentiful especially along the open coast. 



Cladophora gracilis (GrifF,) Harv. 



Phyc. Brit. t. 18; Confcrva gracilis Giiff. in Wyatt, Alg. Danm. Nr, 



97. 



I>escr. Cladophora gracilis Fad. New. Engl. A1g. p. 55. 



Fi 



ff. 



n 



n 



n 



Harv. 1. c. 



-* 



„ Kiitz. Tab. Phyc. 4, t. 23. 



„ „ Harv. 1. c. 



„ vaclorum Kiitz. 1. c. t, 20. 

 FJxsicc. Conferva gracilis Wyatt, Alg. Danm. Nr. 97. 



Cladophora giauccscena Fosl. in Wittr. et Nordst. Alg. exsico. 



Nr. G20. 



L 



W 



Syn. Cladophora gracilis f. borealis Fesl. bcrb. 



This is a still more varying species than the preceding one. 

 There is a great diiFerence between the specimen distributed in 

 Wyatt, Alg. Danm. 1. c. and the northern form that appears in 

 ^xposed localities along the coast of Finmarken, and, if nu- 

 i^erous transitions were not seen, they would hardly be 

 tbought to belong.to the same species. The latter ?s smal- 



