MAR INK. ALGAE FKO.M EASTER I -LAND 



26: 



As to the fructification this has been cleared up long ago by the late 

 Mrs. GePP. 1 The plurilocular sporangia (Fig. 12 a) are formed around the 

 trichostomata; the surface cells grow out to cylindrical or somewhat clavate 

 bodies which are divided by transverse walls into small cells in which the 

 gametes are formed. 



Area of distribution: Chnoospora fasligiata has been found in several 

 localities in the Pacific and on the coast of Venezuela in the Atlantic Ocean. 



Fam. Sphacelariaceae. 



Sphacelaria spec. 



Only some few sterile filaments, even without propagula, were observed: 

 they cannot be determined. 



Fam. Dictyotaceae. 

 Dictyopteris Lamx. 



D. repens (Okamura). — Fig. 13. 



Haliseris rfpe/is Okamura, List of Marine Algae collected in Caroline and 

 Marianne Islands, 191 5 'Bot. Magaz., vol. 30, 19 16, p. 8, pi. 1, figs. 7 — 18). 



This pretty little plant was found creeping upon the base of Galaxaura 

 pascJialis and other algae. The specimens found seem to correspond very well 

 with the description of Oka- 

 MURA. The thallus consists 

 of two layers of cells except 

 in the midrib (Fig. 13 a); a 

 sclerenchymatic rib along the 

 margin of the thallus, as found 

 in D. delicatula, is not present 

 here. Besides this difference 

 it further differs from the West 

 Indian plant, to which it other- 

 wise shows a great resem- 

 blance, by the fact that the 

 hair-groups, well developed 

 and regularly scattered in the West Indian plant, are mostly wanting in the 

 Pacific one or, when present, poorly developed and placed without order. 



Rhizoids like those in the W. I. plant are frequent; they grow out from 

 the midrib and from the margin of the thallus. The rhizoids have a long stalk 

 composed of cells about 100 a long and 33 u. broad being somewhat narrowed 

 at the cross walls. They end in a small coralliform disc. 



Unfortunately all the material was sterile. 



Area of distribution: Pacific Ocean 



Fig. 13. Dictyopteris repens (Okam.) Cross sections of 

 thallus, a through the midrib, b through margin, c. 200 /i- 



1 Barton, Ethel S., On the fruit of Chnoospora fastigiata J. Ag. (Journ. Linn. Soc, Be t. 

 vol. 33, 1897/8, p. 507, pi. 28). 



