384 



St. Croix and St. Thomas, collected by 0RSTED and determined 

 by J. AGARDH, are kept in the Herbarium of the Botanical Mu- 

 seum, Copenhagen. I have specimens which are quite identical 

 with these. They seem to be like a more densely branched form 

 of the present one. 



It seems to me very likely that the specimens I have referred 

 to this species are only forms from more protected places, and 

 those referred to the following species, Hypnea spinella, nothing 

 else but forms from more exposed places. 



This species occurs in more protected places in shallow water, 

 but it has also been dredged in deep sea at a depth of about 30 

 meters. It was found with tetrasporangia and cystocarps in the 

 months of February and March. 



It is a common species along the shores of the islands. 

 Geogr. Distrib.: Seems to occur in most warmer seas. 



4. Hypnea spinella (Ag.) Ktitz. 



KtfTZiNG, Spec. Alg., p. 759. J. AGARDH, Spec. Alg., vol. II, p. 453; 

 Epicrisis, p. 565. 



Sphserococcus spinellus Ag., Spec. Alg., p. 323; Systema, p. 237. 



This plant forms small compact tufts upon rocks. 



The plant is very irregu- 

 larly ramified (Fig. 369); the 

 branches are issued in all di- 

 rections, in some cases with 

 larger distance between them, 

 in others several branches are 

 crowded together. Some of the 

 branches grow out to main 

 filaments, most of them be- 

 come small, short, spinelike 

 branchlets of variable length. 



These much branched fil- 

 aments are felted between 

 each others and further often 

 anastomosing to each others 



Fig. 369. Hypnea spinella (Ag.) Ktitz. by means of rhizoids breaking 



Part of a plant with anastomosing out everywhere from the thai- 

 branches and fertile parts with tetra- 



sporangia (about 10:1). lus (Fig. 369). 



