38 Universitij of California Publications in Botany [Vol.8 



formation of gonidia is not nnifjue in this species. It is similar to 

 that reported a.s taking place in Plenrocapsa entoph ysaloides, and in 

 other undoscribed species which we have observed. In all of these 

 species the contents of all of the cells of a colony seem to divide 

 simultaneously. Any and all of the vegetative cells may produce 

 gonidia without change in size. This is also true of all species of 

 Demiocarpa, Gomphosphaeria, etc. The cell being small the number 

 of gonidia from a cell is small, viz., two to fovir, and it has not been 

 determined positively whether the two divisions necessary- to form 

 four gonidia take place successively or simultaneousl3\ In most of 

 the species in other genera which we have studied the divisions take 

 place successively, and this method may possibly be the one followed 

 by all species. Wille (1906, p. 21) has described and figured what 

 appears to be the same method of gonidial formation in the European 

 Glococapsa crcpidinnm Thur., which he finds near the biological 

 station at Droutheim. He does not look upon this stage in the life 

 history as being the gonidial stage comparable to that of the Chamae- 

 siphonaceae, but speaks of it as the " Aphanocapsa-^iaidmm.'" He 

 concludes that these small cells float away, finally lodge in tide pools, 

 and become the so-called marine species of Aphariocapsa, e.g., A. 

 nvarina Hansg. The facts as we find them here seem hardlj^ sufficient 

 to warrant such conclusions concerning our species. 



There are certain difficulties in the way of a satisfactory placing 

 of this form that have led to a disposition of it as a species of Plenro- 

 capsa. Were it not for the presence of gonidia, it might be placed 

 fairly satisfactorily under Gloeocapsa crepidinum Thuret. The dis- 

 covery of similar gonidia in what Wille refers to Gloeocapsa crepi^ 

 dinum in Norway, strengthens this position. There are, however, pos- 

 sibilities that Wille 's plant may not be the same as that of Thuret and 

 that ours may be different from both. It may be that all Gloeocapsa 

 species may be found ultimately to form gonidia, but it does not seem 

 very probable. In view of the various uncertainties, it seemed best 

 for the time, at least, to refer the California plant to Pleurocapsa. 



3. Pleurocapsa entophysaloides S. and G. 

 Plate 4, figs. 9, 10; plate 7, fig. 30 



Plants forming a dark colored, pulverulent, somewhat mucilaginous 

 stratum, 1-4 mm. thick; single cells spherical, 8-1 0/x diam., in colonies 

 very angular, 4— 8/t diam., forming spherical or variously lobed, fre- 



