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simplicibus, infinris plumæ medias longitudine circiter æquantibus" 

 and this is also sometimes found in my specimens but most often 

 the lowermost ramuli grow longer and the plant must then be re- 

 ferred to Br. plumosa. Other specimens have the ramuli more or 

 less secund like Br. Harveyana but also here we find an even 

 transition to i?n/opsis-plants with distichous ramuli. I prefer therefore 

 to follow Harvey's conception of the species in "Nereis Bor.-Ameri- 

 cana", p. 31, and to consider these different variants as forms of 

 Bryopsis plumosa. 



I have now again revised my Bryopsis-mdXevm\ and have com- 

 pared my material with specimens collected by M lle Vickers at 

 Barbadoes and with the excellent ligures in her "Phycologia Bar- 

 badensis". M lle Vickers has figured, besides Br. hypnoides, also 

 Br. pennata, Br. Harveyana and Br. Leprieurii. Unfortunately she 

 never managed to give any description of these forms. Now I 

 willingly admit that when these forms are typically developed, as 

 in M lle Vickers' above-mentioned figures, they are easily disting- 

 uished from each other and from Br. plumosa, and the specimens 

 I have seen from M Ue Vickers' Herbarium seem also to be rather 

 typical; but it is quite otherwise with my material. In this I have 

 found almost no quite typical forms. That form which was most 

 typically developed was Br. Harvey ana but often, even in the same 

 tufts, forms occurred with scattered ramuli like Br. Leprieurii or 

 with the ramuli more or less distichous, thus transitions to Br. plu- 

 mosa or Br. pennata. Of the pennata form some typical or rather 

 typical specimens also occurred, but most often the lowermost 

 ramuli grow somewhat longer, and they may therefore be referred 

 to Br. plumosa. By reason of this fact, therefore, I have no hesi- 

 tation in considering these forms as varieties of Bryopsis plumosa. 

 Only the study of living plants, I think, can give an answer to the 

 question, how far these forms are to be considered as species or 

 not. In this connection I may also quote what Collins writes in 

 u The green Algæ of North America", p. 405; U B. pennata, B. Le- 

 prieurii and B. Harvey ana are certainly closely related; only con- 

 tinued study of living plants will settle the question of their di- 

 stinctness. That the three last named are kept separate here is 

 chiefly due to their being so kept by Miss Vickers, who studied 

 and collected them at Barbados". From this it seems clear that 

 Collins, who has certainly seen a good many specimens of these 

 forms, personally has arrived at the same conclusion as I have. 



