774 



arbilrariness, parlly because we know so very little as yet about the 

 distribution of many algæ, partly because several algæ are distri- 

 buted so as to make it almost equally juslifiable to refer them to 

 different groups. Whilst Reinke and Kuckuck leave the Chloro- 

 pliyceæ and the Cyanophijceæ out of consideration , as our know- 

 ledge of these piants is especially defective, I side with Rosen- 

 vinge 's opinion, however, that it is more correct to mention them 

 here, as the species belonging to these orders are as important 

 from a phytogeographical point of view as those of the Rhodo- 

 phyceæ and Phæophyceæ. The species hitherto found only on the 

 Færoes are all referred to the cold-boreal group. 



SUMMARY OF THE FÆROESE MARINE ALGÆ. 



I. Rhodophyceæ. 



83 species. 



A. The arctic group. 

 O species. 



B. The siibarctic group. 

 Subdivision 1. 6 species. 

 Rhodophyllis dichotoma. 

 Halosaccion ramentaceum. 

 Ptilota pectinata. 

 Rhodochorton penicilliforme. 

 Phymatolithon compactum. 

 Lithothamnion læve. 



Subdivision 2. 14 species. 



Porphyra miniata. 

 Conchocelis rosea. 

 Chantransia efflorescens. 



— virgatula. 



Harveyella mirabilis. 

 Phyllophora Brodiæi. 

 Actinococcus subcutaneus. 

 Euthora cristata. 

 Rhodymenia palmata. 

 Delesseria sinuosa. 

 Rhodomela lycopodioides. 

 Odonthalia dentata. 



Ptilota plumosa. 

 Lithothamnion glaciale. 



C. The boreal-arctic group. 

 10 species. 

 Bangia fuscopurpurea. 

 Porphyra umbilicalis. 

 Chantransia secundata. 

 Ahnfeltia plicata. 

 Polysiphonia elongata. 

 Antithamnion Plumula. 

 Ceramium rubrum. 

 Rhodochorton membranaceum. 



— Rothii. 



Hildenbrandia rosea. 



D. The cold-boreal group. 

 38 species. 

 Erythrotrichia ceramicola. 

 Porphyra coccinea. 

 Chantransia Alariæ. 



— Daviesii. 



Choreocolax Polysiphoniæ. 

 Gigartina mamillosa. 

 Phyllophora membranifolia. 



