312 joiis i{(*vK i'Ki i;usi .\ 



piinniforme ncarly always arc lateral, in .S. lomcnlosuni, on Ihe othcr 

 hånd. inlercalarv, at times, howcver, lateral. Thiis a sliarj) (lisliiution 

 botwecn the two sjiecies can evidently not be drawn. and I therefore 

 preler to t'oUow Hornet et l'lahault in considerinj^ tlieiu as one species. 



In the Icclandic spceimens Ihe diameter ol" the threads was 17 — 31 /ti, 

 possesing inlercalarv as well as lateral heterocysts. 



.S. jHinnifoinw is apparently an exclusively terrestrial form tlirivin«^ 

 on walls, rocks, and trecs. but frcciuent nioisleninj; is. liowever, undoub- 

 tcdh' a condition of existence. 



01" the 4 Icelanilic samples which contained the sjjccies in (juestion, 

 threc orij^inated from the hot sprinj^s. I assume that it is ralher the 

 vapour from the sprin<^ than the heat which is favourable to the f»ro\vlh 

 of this alf^a. To my knowledge it has not previously becn found in the 

 vicinity of hol springs. 



Stigonema minutum Hass. 



Bornet et Flahault. Revision III p. 72. Witlr. et Xordst. Alg. exsicc, 

 nr. 1008. 



E. Icel. Vallanes, among mosses on a knoll in bog ""^^/e 1914. — 

 S. Icel. Almannagjå. on rocks; in a place over which water frccpienlly 

 was trickling '^^ 1914. Hcvkjavik, on a stone in a depression wilh 

 water . H. J.)! ^8/4 i897. 



Area : All conlinents. Greenland. Alaska, Færoes. Lappland. 



S. minulum grows most frecjuently on rocks, stones, walls or trunks 

 of trees and generally in piaces where it may be moistened rather often. 

 However. it is able to grow in water, too. In tiie sam])le from Vallanes 

 it appearcd in a corallaceous branched form, mentioned by Bornel et 

 Flahault I. c. p. 74) and corresponding to some extent to S. coralloules 

 Kutz. iTab. phyc. II, tab. 34, VI. The uppermost branchings, however, 

 exhibited dislinctly the features characterislic of .S. minutum, but it may 

 be extremcly diflicult to rccognise it in this form. 



Stigonema turfaceum Herk.i (looke. 



liorncl el Flaliaull. Revision III p. 74. 



Sirosiffhon f)uli'in(ilus Kiitz. Tab. phyc. II, tab. 36, fig. I. 



E. Icel. Hog al 300 111. above sea-ievcl behind Scyi^isfjon^ur. moss 

 With algæ ''V« 1914. 



Area: .Ml conlinents, Færoes, Greenland. 



Most frequently found as a terrestrial plant, on earlli. rocks, Irces 

 etc. that are more or Icss damj). On the above-nientioned Icelantlic lo- 

 cality it was but scanlily represented. At the time when the coUeclion 

 took place the locality was stil! very wet owing to the faet that the 

 snow on the mountains was slill thawing; but lalcr in Ihc summer the 

 algæ on this locality will undoubledly be lial)le to sulfer from a con- 

 siderable drought. 



