F. Børgesen : Rhodophyceæ of the Danish W. Indies. 



43 



the present species, and the sporangia are rounder and have not 

 the thick wall of Acr. robustiim. 



Found upon Sargassiim vulgare in sheltered place. 



St. Thomas: The Harbour. 



13. Acrochætium bisporum Borgs. 



Chantransia bispora Borgs., Some new or Httle known West Indian 

 Florideæ, II ("Botanisk Tidsskrift", vol. 30, 1910, p. 178). 



IUI 



OOO 



Fig. 41. Acrochætium bisporum Borgs. A, part of a plant with sporangia 

 with two spores. B, part of a plant with monosporangia. C, sporangia 

 with two spores. Z>, cells with chromatophore and pyrenoid. E, a young 

 plant. F, G, H, I, basal parts of plants. {A, B. about 120 :1, F, G, I, about 



250:1, C,D,E,H, about 350:1). 



In the former description of this plant, I have pointed out 

 that it is perhaps nothing more than a variety of Acrochætium 

 Hypneæ. I had hoped when looking through my collections 

 to refmd it again and by a renewed examination be able to 

 settle this question. 



