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



233 



Geogr, Distrib. : Mediterranean Sea, warmer shores of the Atlantic 

 Ocean. 



Subfam. 6. Spyridieæ. 



1. Spyridia filamentosa (Wulf.) Harv. 



Harvey, W. H., in Hooker, Brit. Flora, vol. II, 1833, p. 336; Manual 

 Brit. Alg., 1841, p. 101 ; Phycologia Britannica, pi. 46; Nereis Bor.-Am., 1853, 

 part II, p. 204. Agardh, J., Spec. Alg., vol. II, p. 340; Epicrisis, p. 268. 

 Farlow, W. G., Mar. Alg. of New England, 1881, p. 140, pi. X, fig. 1 and 

 pi. XII, fig. 2. Hauck, F., Meeresalgen, p. 115. De Toni, Sylloge Alg., 

 vol. IV, sect. Ill, p. 1427 (ubi synomyna pluria). 



Fucus filamentosus Wulfen, Cryptogama aquatica in Roemer's Archiv 

 für die Botanik, III, 1803, p. 64. 



Spyridia filamentosa is a very variable plant as is sufficiently 

 clear from the many names the different forms have received 

 in the course of time. To understand this we need only to 

 consider the many different forms Kützing has figured in 

 "Tabulæ phycologicæ", having put 

 them down as separate forms (comp. 

 De Toni, 1. c). It is, of course, 

 always a difficult thing to decide, 

 whether any of these forms really 

 ought to be considered as a proper 

 species or not. But to judge from 

 the West Indian material the species 

 seems to be a very plastic plant, 

 highly influenced by the external 

 conditions. In the West Indies I 

 have found it in more sheltered 

 places and in shallow water. It is 

 common in lagoons and bays, but 

 the mechanical influence of the waves 

 may often he strong even in such 

 places e. g. in certain places in 

 the harbour of Charlotte Amalia. 

 Light is another factor having much 

 influence upon the shape of the plant. 

 Of course this varies a good deal 

 according to whether the plant is 

 growing upon coral reef or atta- 

 ched to the roots of mangroves, thus Fig. 222. Spyridia filamentosa 



growing in the shade of these trees. (^"1^/) "^J^- ^^'^ fj^^^""^' 



.■,.-,,. . , men from the coast of St. Croix 



And again whether it grows in clear near Christiansted. (About 16:1). 



