Contribution. I. 



31 



^^1 



The present plant is litoral, growing in rock-pools on 

 yather exposed shore Specimens coUected in the later half 

 of July were sparingly tetrasporiferous. 



Di. tribution: Only found at Syltefjord, local, scarce. 



Gen. Dumontia (Lamonr.) J. G, Ag. 



Spee. Alg. 2. p. 348, Lamour. Eas. p; 183; char. mut. 



Dumontia filiformis (Fl. Dan.) Grev. 



Alg. Brit. p. 165; Ulva filiformis Fl. Dan. t. 1480. 



f. typica. 



Beser, Dumontia filiformis J. G. Ag. Spee. Alg. 2, p. 349. 



i^ 



Fig. 



» 



» 



Harv. Pliyc. Brit. t. 59 et 357 B. 



f. crispata Grev. 



Alg. Brit. p. 165. 



p. 51, 



Beser. Dumontia filiformis /S crispata J. G. Ag. Spee. Alg. 2, p. 350 



Syn. Ulva filiformis Wg. Fl. Lapp. p. 508. 



^ jj Sommerf. Suppl. p. 187. 



Gastridium filiforme Sommerf. in Act. Nidros. 



The form crispata, as it appears at East-Finmarken, is 

 not distinctly marked. Here it is narrower and less twisted 

 than more southward, but on the other hand, it diifers from 

 f, typica by its greater firmness and by the inner layer of 

 cells beinglarger. However, transitions are pretty common. 

 It seems to prefer freshwater-streams between tides. 



The present species is litoral, occurring most commonly 

 in rock-pools or other caves between tides, attached to stones, 

 shells or sometimes to lucaceae. It of ten grows gregarions 



4 



in rather considerable numbers, on open shore as well as in 

 sheltered places, and it even enters the inner end of the 

 greater bays. On much exposed places it becomes rather 

 reduced in si^ie. The ] argest specimens I have seen had a 

 length of 35 cm., yet mostly smaller, sometimes only 5 cm. 

 It has been tåken with tetrasporangia in the later half of 



Jw^e, m Julj^, aiid w tho begimaing of August (richl^). % 



nflWS'. 



