MARINE ALGAE FROM EASTER ISLAND 



301 



Polysiphonia Grew 



P. spec. 



A small antheridial plant with four pericentral cells. From a decumbent 

 filament fixed to the substratum by means of rhizoids erect filaments arise. 

 The filaments are about 50 a thick and the length of the cells about 80 ;j.. 



The specimen bears considerable likeness to ASKENASY's 1 figure of an 

 antheridial plant of Polysiphonia mollis Hook f. et Harv. 



Herposiphonia Xaeg. 



H. tenella (C. Ag.) Naeg. — Figs. 42, 43. 



Nageli, C, Herposiphonia (in Schleidex und N agelt, Zeitschr. f. wiss. Bot., 

 3 — 4 Heft, 1846, p. 238, tab. VIII). Falkenberg, P., Rhodomelaceen, p. 304. 

 Borgesen, F., Marine Algae D. W. I., vol. II, pp. 286 and 472. 



In referring the plant from Easter Island to this species it must be pointed 

 out that before we know the male plant no exact determination can be made; 

 cfr. my remarks 1. c, p. 470. 



Fig. 42. Herposiphonia tenella (C. Ag.) Naeg., part of specimen growing on Valonia. C. * 6 /i- 



Sterile specimens were found on Valonia ventricosa. They had 5— S peri- 

 central cells. The creeping, prostrate main filaments are fixed to the wall of 

 the host by means of vigorous rhizoids quite in the same way as found in the 

 West Indian plant. 



1 Askexasy, E., Ueber einige australische Meeresalgen. Flora, 1894, p. 13., pi. 4, fig- 22 - 



