Contribution. I. 



139 



f. pannosa (Aresch.) nob, 



Conferva pannosa Arescli. Alg. Scand. exsicc. Ser. 1, Nr. 16. 

 Beser. Eliizocloninm pannosum Kiitz. Spee. Alg. p. 384. 



Conferva iniplexa h. Aresch. Phyc. Scand. p, 434: excl. syn. plur. 



r 



Fig. Rliizoclonium pannosum Kiitis. Tab Pliyc. 3, t. 70 I. 

 Exsicc. Conferva pannosa Åresck 1. c. 



Syn. Conferva obtusangula Lyngb. Ilydr. Dan. p. 159. 



„ „ Sominerf. Suppl. p. 195. 



I 



The typical form of this species forms thin but often 

 extenaive strata on rocks, in shaUow clefts of rocks, or in 

 the margin of rock-pools, sometimes together with other spe- 

 cies, as Cladophora, Spongo^norpha and Ehodochorton Bothii. 

 It is in general less curved and has fewer rhizoid branches 

 than the forra figured by .Harvey in Phyc. Brit. 1. c, 

 but I have seen specimens which fnlly correspond with the 

 quoted figure. The form distributed by Areschoug in ' 

 Alg. Scand. exsicc. Nr. 136 appears to be a transition be- 

 tween /. iypica and f. temiior W i 1 1 r. et N o r d s t. Alg. 

 exsicc. Nr. 625, though most nearly related to the former. 

 The form that I have called /. vaUda is distinguished from 

 the typical one chieflyby its coarseness and mode of growth. 

 It occurs in narrow and somewath deep clefts of exposed 

 rocks, forming rough, crispate-elevated cushions. The threads 

 diffør between 26 and 45 [x in thickness, nsually about 

 30 jx. A form very nnlike the latter in habit but other- 

 wi.se nearly related to it is the above mentioned /. pannosa 

 It grows on posts or other woodwork, or sometimes on 

 rocks, and forms rather thick and dense layers with a un- 

 dulate-lacunosed surface. In coarseness and the length of 



4 



the cells it corresponds with f. valida^ but the rhizoid bran- 

 ches are numerous and longer than by the latter. 



The present plant lives in the upper part of the lito- 

 ral zone, sometimes even a little above high-water mark, on 



open coasts as well as sheltered ones. Specimens with zoo- 



1 



v 



