FRESHWATER ALGÆ^ 



BY 



F. BØRGESEN. 

 (With piates VII— X). 



IN the years 1895, 96 and 98 I sta^^ed a coiiple of months at a 

 time in the Færoes, for the pnrpose of stiidying the algæ-vegetation 

 along the coasts, and have also on my frequent trips round the 

 islands gathered a considerable material of Freshwater Algæ. Pro- 

 fessor Warming, Mr. Jensen, Mr. Ostenfeld, Mr. Jonsson, 

 and others have during their stay on the islands made considerable 

 collections from numerous localities and at different seasons. In 

 this way a comparatively large material has been at my disposal 

 and the result has therefore been that the niimber of hitherto 

 known freshwater algæ from the islands has been considerably 

 increased which was indeed to be expected as the islands have not 

 been examined by any algologist since Lyngbye's days. 



Jørgen Landt^ is the first who has, as far as I know, given 

 a fairly intelligible report of the freshwater algæ from the Færoes; 

 he mentions a few freshwater species siich as Tremella Nostoc which 

 judging from his description seems to be Nostoc commiine, Bijssiis 

 botrijoidcs which may be Pleiirococciis viilgaris and Conferva riviilaris 

 which perhaps is Ulothrix zonata and a few other species with re- 

 gard to which one cannot decide, what is actually meant. 



In the year 1817 Hans Christian Lyngbye, traversed the 

 Færoes and in his classic work: »Tentamen Hydrophytol ogiæ 

 Danicæ« he mentions more than 30 species of freshwater algæ 

 from the Færoes. By means of original specimens in Lyngbye's 



^ When this paper was ready for the press a resumé of it was read Ijefore 

 the »Naturhistoriske Forening«, Copenhagen, in 1899. (Vidensk. Medd. f. d. nat. 

 Forening, Kjøbenhavn 1899, p. 317). 



- Jorgcn Landt: »Forsøg til en Beskrivelse over Færoerne , Kjøbenhavn 1800. 



