800 



Agariim Tiirneri, Chlorochijtriiim Schmitzii, Ulothrix siibftaccida, 

 Acrochæte parasitica, Urospora Hartzii, Rhizocloniiim pachydermiim'^, 

 Acrosiphonia penicilliforme ; 22 species in all. 



Subdivision 2: Phæostroma piishilosiim , Haplospora globosa, 

 Chlorochijtriiim Cohnii, Ch. dermatocoiax , Cladophora hirta: 5 spe- 

 cies in all. 



The boreal-arctic gro up: Chantransia microscopiai, Oscilla- 

 toria amphihia, O. tenuis^; 3 species in all. 



The cold-boreal group: Lithothamnion intermedium, Ecto- 

 carpiis Pringsheimii, E. penicillatiis, Sphacelaria radicans, Dictyosiphon 

 Chordaria, Epicladia Fliistræ, Ochlochæte ferox, Vaiicheria intermedia, 

 V. sphærospora ; 9 species in all. 



Thus we see, that by far the greater part of these species be- 

 longs to the arctic and the coldest subdivision of the subarctic group; 

 it is not probable that any of these species will be found at the 

 Færoes. On the olher band, some of the few species referred to 

 the other groups will no doubt be found to grow there. 



This comparison thus leads to the conclusion that the Færoese 

 algæ-tlora includes a great number of southern forms wanting at 

 Greenland, whilst Greenland has a great number of arctic species 

 not found at the Færoes. 



Lastly we may make a comparison with the algæ-Ilora of 

 North- America. It is a well-known faet that in spite of the 

 great distance separating the algæ- flora of North -Europe from 

 that of the North-American coast of the North-Atlantic Ocean, they 

 still have a great many species in common. Our knowledge of 

 the North-American algæ -flora we owe firstly to Farlow's well- 

 known paper (20) which is now somewhat antiquated, however, 

 as it is 25 years since it was published, secondly to later works of 

 Farlow% Collins and others. The latter author published in 1900 

 a list (13) of the North-American algæ, which has been used toge- 

 ther with Farlow's above-mentioned paper as a basis for this 

 comparison. Of the species mentioned in this list about 130 are 

 also found at the Færoes, that is, more than one half (60 %) of 

 all the Færoese species. Fa ri o w has already cailed our attention 

 to the great resemblance between the algæ-llora of both sides of 

 the North-Atlantic Ocean; he likewise mentions (20, p. 4) some of 

 the commonest species that grow both east and west of the Ocean. 



^ Found in freshwater at the Færoes. 



