THE FRESH-WATER CYANOPHYCEÆ OF ICELAND 



303 



>^;a3 



walls of the cells were often scarcely distinct. Cells one-half to twice as 

 long as broad. Cell contents granular. The cells were sometimes cy- 

 lindrlcal, at times somewhat barrel-shaped. Heterocysts 10—11 u in dia- 

 meter, 22— 39.6// in length. 

 The colour of the plant 

 mass (when dried) was 

 macroscopically seen blue- 

 green corresponding to 

 codex nr. 352. 



On the assuniption that 

 Se. variiirn Kiitz. is syno- 

 nymoiis with Se. ehryso- 

 chlonim Kiitz., which Bor- 

 net et Flahault have pro- 

 ved tlfrough their exami- 

 nation of authentic spe- 

 cimcns, I now identify the 

 plant in question with Se. 

 nariiim Kiitz. It bears 

 namely a specially close 

 resemblance to Ki'itzing's 

 figure of Se. chrysochlorum 

 in Tab. phyc. 1. c. On the 

 other hånd, it does not 



seem to me that his figure of Se. variuin represents an absolutely good 

 resemblance. The Icelandic alga is also, with regard to habitat, in ac- 

 cordance with Se. ehrysoehlorum which has been found at Euganeæ, 

 undoubtedly at the hot springs. Strangely enough do neither Bornet et 

 Flahault nor De-Toni (Sylloge Alg. V p. 513) record this locality. Se. 

 samoense Wille (1913 p. 145; 1914 p. 11, tab. I, figs. 15—18) is probably 

 also related to this species. 



Scytonema tolypotpjchoides Kiitz. 



Bornet et Flahault, Revision III p. 100. Wittr. et Nordst. Alg. ex- 

 sicc, nr. 768. 



E. Icel. Sey6isfj6rdur, bog at 300 m., moss with algæ ^^/e 1914.— 

 S. Icel. Gnmsta5ir, mud from "Floi". ^Vi 1905 (H. .1.)! 

 Area : Eur., Afr., N. Am. 



This species, which has been found but rarely, thrives best in 

 water, floating free. According to Allorge (1921 p. 621) it is characte- 

 ristic of the water in Sphagnum-bogs which is but poor in mineral. On 

 one of the Icelandic localities it was found under such conditions that 

 it is permissible to conclude that it will dry up during the summer. 



Fig. 13. Scytonema varium Kutz. (X600). 



Scytonema mirabile (Dillw.^ Bornet. 

 S. fujiiratnm Bornet et Flahault, Revision III p. 101. 

 S. Chlhonoplastes Liebm. Fl. dan., tab. 2398.2. Liebm. 1841 p. 339; 

 Born. et Flah., Rev. III p 111. 



.S. ehrysoehlorum Rab. Algen, nr. 1096. 



