Contribution. I. 137^ 



fers from typical specimens chiefly by its darker colour, 

 greater rigidity, coarseness, shorter cells and thicker cell- 

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

 pears to be so nearly related to the latter that it hardly 

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

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

 mens even still slender than 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 is litoral, occurring in pools in 

 the upper part of the region. It thrives best on open coast, 

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

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

 in the later half of July and in August. 



Distribution: Pretty common and at several places ra- 

 ther plentiful especially along the open coast. ; ; 



Cladophora gracilis (Griff.) Harv. 

 Phyc. Brit. t. 18; Conferva gracilis Griff, in Wyatt, Alg. Danm. Nr. 

 97. ; 



Descr. Cladophora gracilis Farl. New. Engl. A'g. p. 55. 



„ „ Harv. 1. c. 



Fig. „ „ Kiitz. Tab. Phyc. 4, t. 23. 



„ „ Harv. 1. c. 



„ vadorum Kiitz. 1. c. t. 20. 

 Exsicc. Conferva gracilis Wyatt, Alg. Damn. Nr. 97. 



Cladophora glaucescens Fosi. in Wittr. et Nordst. Alg. exsicc. 



Nr. 620. 



Syn. Cladophora gracilis f. borealis Fosl. herb. 



■■•• .\ 

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



There is a great difference between the specimen distributed in 

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

 exposed localities along the coast of Finmarken, and, if nu- 

 merous transitions were not seen, they would hardly be 

 thought to belong to. the same species. The latter is smaj,- 



