29 365 



6. Caulerpa sertularioides (Gmel.) Howe. 



M. A. Howe, Phycological studies II, p. 576. 



Fucus sertularioides Gmelin, Historia Fucorum p. 151, tab. 15, fig. 4. 

 Caulerpa plumaris (Forsk.) Ag., Weber van Bosse, Monographie p. 294. 

 Exsicc. WiTTU. & NoRn.ST., Algæ exsiccatæ, Nr. 1585. 



That Fucus sertularioides Gmel. 1. c. is without doubt the same as Caulerpa 

 plumaris (Forsk.) Mme. Weber van Bosse has already expressed in the following 

 wav: "D'après les lois de la priorité le nom de sertularioides proposé par Gmeun 

 devrait être réinstallé, car Gmelin a non seulement décrit la plante, mais il en 

 a aussi donné une figure très exacte. On s'est cependant tellement habitué à 

 employer le nom de C. plumaris, que ce nom est consacré par l'usage." Even if I 

 sympathise with this last remark of Mme. Weber van Bosse, one is I think, at all 

 events in a case like this where there is no doubt in the matter, forced to follow 

 the laws of priority, and therefore as Howe has done call the plant with the name 

 first proposed by Gmelin. 



f. typica (compare below). 



f. brevipes (J. G. Ag.) Weber van Bosse, Monographie p. 294. 



f. longiseia (J. G. Ag.) Weber van Bosse, Monographie p. 295. 



f. Farlowii Weber van Bosse, Monographie p. 295. (Fig. 11.) 

 Caulerpa sertularioides is a distinctly littoral alga which is very common from 

 the surface of the sea down to a depth of some few meters. It occurs both on 

 rather exposed coasts and in quite sheltered localities. On exposed coasts it is 

 partly what I call f. typica, characterized by its rather thick, not very densely 

 placed pinnules, partly forma brevipes that occur. They often grow in rather large 

 tufts sometimes together with other Caulerpas, e. g. C. taxi folia, and wave to and 

 fro in the swell. 



In localities where it is steadily exposed to some swell, e. g. at the landing 

 place at Christiansfort in St. Jan, I have found a form distinguished by having a 

 long and narrow leaf which I think is to be considered as a wave-beaten form, 

 similar to the forms of C. racemosa var. occidentalis and var. uvifera with long 

 erect shoots I have found in the same locality and which will be mentioned 

 later on. 



While the two above mentioned forms are for the most part to be found on 

 more exposed coasts, forma longiseta, characterized by its longer, thinner and 

 densely placed pinnules, is especially restricted to the more sheltered localities. 

 It is thus rather common in the lagoons, e. g. the lagoon of" Christianssted, where 

 it creeps in the soft bottom; but I have also found this form in a somewhat more 

 exposed locality, e. g. behind Long Reef near Little Princess on the north side of 

 St. Croix, but here it is united by many transitional forms with the typical form 

 or with forma brevipes. In shallow water it occurs down to a depth of about 

 2 — 4 meters. In such greater depths as 10 — 15m. in which Svedelius (I.e. p. 115) 

 has found it on the shores of Ceylon I have never seen it. 



