MARINE ALGAE FROM EASTER ISLAND 



3°3 



Dipterosiphonia Schmitz. & Falkenb. 



D. dendritica (Ag.) Falkenb. Fig. 44. 



Falkenberg, P., Rhodomdaceen, p. 324. 

 Borgesen, F. f Mar. Alg. 1). YV. I., p. 302. — 

 Huichinsia dendritica Ag., Systema, p. 146; Spec- 

 ies Alg., vol. II, p. 104. — Polysiphonia dendri- 

 tica J. Ag., Spec. Alg., vol. II, pars 3, p. 916. 



Some small sterile fragments were found 

 on Laurencia clavifortnis. In one respect it 

 differs essentially from the West Indian plant, 

 as described by me 1. c; in this, the branchlets 

 with definite growth are always undivided, 

 while, in the Easter Island form, they often 

 bear a few spine like side branches. These 

 are mostly situated above the middle of the 

 branchlets and their number rarely surpasses 

 two or three. They form acute angles with 

 the main branch. 



Otherwise, the Easter Island plant seems 



to agree perfectly with the West Indian one. 



Like this it has five pericentral cells, three 



on the upper side, two below, and it is attached 



to the host plant by meatus of vigorous hapters, u. D 4 . f „.., 



1 J *= i _ ' P]g. 4^j. Part of a specimen ot Diptero- 



which pierce the sides of the host plant like siphonia denaritica (Ag.) Falkenb. C. so /i. 

 claws. 



Area of distribution: Brazil, West Indies, Australia, Easter Island. 



Dasya C. Ag. 

 D. villosa Harv. 



Harvey, W. H., Algae of Tasmania, London Journal of Botany, vol. Ill, 1844, 

 P- 433- 



The specimens had been preserved in formaline and were in a state of 

 dissolution, falling to pieces at the least touch. Nevertheless I think the 

 determination is right, the plants being in good accordance with the descrip- 

 tion of Harvey and with Kl'TZING's Figure; I have also been able to compare 

 them with a specimen of Harvey's Australian Algae, No. 218 from Van 

 Diemen's Land. 



When young the stichidia are rather short and thick, ovate to lanceolate, 

 when older they become longer and subcylindrical with attenuated summit, 

 but perhaps the great length is due to the bad preservation, all the tetraspores 

 having fallen out and the cells getting more or less separated. 



Area of distribution: Tasmania, Easter Island. 



