438 University of Calif orm^a PuMications in Botany [Vol. 6 



Dermocarpa hemisphaerica Setchell et Gardner sp. nov. 



Plate 37, fig. 21 



Cellulis epiphyticis, solitariis, hemisphericis, a superficie piano 

 adhaerentibus 18-21/i, diam. basali, 10-13/x altis; contentu celliilarum 

 laete caenileo-viridi, homogeneo ; multiplicatione per partitiones con- 

 tinuas contentus toti gonidia spheriea 0.8-1.2/t formanti. 



Cells epiph.ytic, solitary, hemispherical, attached by the flat plane 

 surface, 18-21/i. diam. at the base, 10-13/i, high ; contents of cell bright 

 blue-green, homogeneous; cell wall hyaline, moderately thick, homo- 

 geneous; reproduction by successive divisions of the whole protoplast, 

 forming spherical gonidia 0.8-1.2^ diam. 



Growing on Khodochorton Rothii in moist shaded places along 

 high-tide level, or even above. Moss Beach, San Mateo County, Cali- 

 fornia. The above locality is the one from which the type material 

 has been obtained, but the plant has been observed growing on the 

 same host at a number of different localities along the California coast. 



Dermocarpa hemisphaerica is a somewhat aberrant plant. The 

 individuals are small, mostly solitary, and multiplication is wholly 

 by means of gonidia. In size and distribution on the host it resembles 

 Xenococcns in the early stages of development of that genus, but 

 differs from it in not having increase by means of vegetative 

 cell divisions. In its solitary habit and method of reproduction it 

 resembles Cyanocystis, but differs from that genus in its method of 

 escape of gonidia, those of D. hemisphaerica escaping through a small 

 opening at the apex of the gonidangia, and those of Cyanocystis escap- 

 ing by means of a circumscissile splitting of the gonidangia. It seems 

 more nearly to fulfil the requirements of the genus Dermocarpa, as 

 now generally understood, than any other genus of Chamaesiphon- 

 aceae. It differs however from all of the species of that genus thus 

 far described, so far as I know, in the method of the formation of 

 gonidia. They are formed in this species by successive divisions of 

 the contents of the gonidangia (pi. 37, fig. 21), those in the other 

 species being formed by simultaneous division. In this respect it is 

 like some species of Pleurocapsa. 



Dermocarpa hemisphaerica is commonly associated with Chlorogloea 

 cmiferta and Dermocarpa suffulta described in this paper. The early 

 stages of the development of D. hemisphaerica and D. suffulta are very 

 similar to each other, but they soon differentiate into their character- 

 istic shapes, and at maturity are very readily distinguishable. Chloro- 

 gloea c&nferta is very frequently in such abundance as to completely 

 cover up the other two species with which it is so frequently" associated 

 here ; hence this condition along witli the presence of diatoms and 

 other foreign material, has made the separation of these forms some- 



