1925 1 Setchell-Gardner: Mekmophyceae 503 



more or less united into a disk or irregular membrane probably pre- 

 cede the development of the compacted or agglutinated erecl filaments, 

 thus assisting in linking the Elachisteaceae with the Ectocarpaceae 

 and the more pulvinate Myrionemataceae. 



Key to the Genera 



Basal cells of the thallus more or less firmly agglutinated; paraphyses present 



13. Elachistea (p. 503) 



Basal cells of the thallus loosely interwoven; paraphyses wanting 



14. Gonodia (p. 505) 



13. Elachistea Duby 



Frond tufted or expanded, composed of a colorless basal pseudo- 

 parenchymatous mass of cells, which may or may not penetrate the 

 host, and arising from these, closely compacted ''paraphyses," long 

 free assimilating filaments and numerous long hairs, present only in 

 certain species; reproduction by zoosporangia and by gametangia, 

 both borne among the "paraphyses." 



Duby, Bot. Gall., 1830, p. 972. 



We have adopted the original spelling of Duby who founded the 

 genus on the Conferva scutulata Engl. Bot., pi. 2311. The type species 

 of the genus, E. scutulata, was collected in 1811 by Mr. Borrer at 

 Brighthelmston on the coast of Sussex, England. There seem to be 

 two species within our territory, both occurring to the north of the 

 California coast. Opospermum of Rafmesque (Precis decouv. et trav. 

 somiol., 1814) seems, from the description, to be unidentifiable, at 

 least by no means certainly to apply to any member of Elachistea. 



Key to the Species 



1. Paraphyses decidedly curved, strongly moniliform, with upper cells as long or 

 longer than broad 1. E. fucicola (p. 503) 



1. Paraphyses straight or slightly curved, barely constricted at the dissepiments, 

 with upper cells shorter than broad 2. E. lubrica (p. 504) 



1. Elachistea fucicola (Velley) Aresch. 



Plate 38, figs. 33-35 



Thallus fasciculate, 4-7 mm. high, the basal portion composed of a 

 small, usually hemispherical, dense, lubricous mass of closely inter- 

 twined branched filaments, giving rise to numerous free paraphyses, 

 sporangia and assimilating filaments; paraphyses clavate, uncinate, 

 moniliform, 170-200^ long, 18-24/a diam. above, 1-W/x diam. below; 



