F. Børgesen: Rhodophyceæ of the Danish W. Indies. 373 



at a definite conclusion, but to attain this result a monographic 

 examination of a rich material af a large number of species is 

 necessary in order to determine how the plants vary under different 

 conditions. 



How useful the examination of a large number of specimens is, 

 Collins and Hervey, in their work: "The Algæ of Bermuda", 

 have shown, when they had the opportunity of examining a large 

 collection of specimens which had previously been referred to the 

 three species Gr. Wrightii, Poitei and cornea. They arrived at the 

 conclusion that they „can find no line of demarcation between 

 the three species mentioned". They therefore refer all of them 

 to one and the same species: Gr. Wrightii. 



Some of the ten species recorded in the following Hst have been 

 recorded from the islands by former investigators. Of several 

 of these species I have found only very few specimens or such 

 about which I feel a great doubt. This applies for instance to 

 what is called Gr. compressa. I greatly doubt whether the few 

 specimens I have referred to this species really belong to the 

 European species and it is the same in the case of some dried 

 specimens from St. Croix determined by J. Agardh and kept 

 in the Botanical Museum, Copenhagen. 



1. Gracilaria confervoides (L.) Grev. 



Greville, R. K., Alg. Brit., p. 123. Harvey, Phycol. Brit., pi. 65. 

 J. Agardh, Spec. Alg., vol. II, p. 587, Epicr. p. 413. Thuret et Bornet, 

 Etudes phycologiques, p. 80, pi. XL. 



For more references see De Toni, Sylloge Alg., vol. IV, Sect. II, p. 431. 



The specimens referred to this species have a tissue of very 

 large cells in the middle of the thallus, often more than 1 mm 

 in diameter. The walls of the cells are very thin. This tissue is 

 surrounded by a cortical layer one or two cells thick. When dry, 

 the thallus quite collapses. 



Plants with cystocarps were gathered in the month of Ja- 

 nuary. 



This species occurs in shallow water and in sheltered places. 

 It often grows in localities with a sandy bottom sprinkled with 

 stones to which the alga is attached. 



