432 University of California Puhlications in Botany [Vol. 6 



practically independent plants, the descendants of the same number 

 of individual cells — a simpler type. In the second case, the colony 

 would consist of a single plant, all of whose cells would be the 

 descendants of but a single cell — a more complex type. The plants 

 which are here placed in the genus Radaisia follow the latter method 

 of development. 



The chief difference between the new species described here and 

 the original species of the genus is the method of gonidia formation. 

 In the type of the genus they are formed by successive divisions of 

 the cell contents, while those proposed here are formed by simul- 

 taneous divisions of the contents of the gonidangium. 



In segregating the plants of my collection the following characters 

 have been used to distinguish the genera Hyella and Radmda: 

 Those forms with erect filaments, more or less branched and distorted, 

 arising from basal filaments on the surface of the substratum and 

 growing into it, and having gonidangia at their bases near the surface 

 of the host, have been assigned to the genus Hyella. Those forms 

 with erect filaments, simple or complex, closely compact, more or less 

 parallel, not at all or only slightly branched, arising in the same 

 manner as those mentioned above, but extending away from the 

 host, and with gonidangia on the outer free ends, have been placed in 

 the genus Radaisia. 



Chlorogloea conferta (Kuetz.) Setchell et Gardner comb. nov. 



Plate 36, fig. 6 



Coloniis tuberculiformibus in magnitndine et in forma variabili- 

 bus; cellulis angularibus, 0.8-1.2|U, diam., paululura longioribus quam 

 crassis, in matrice densa, copiosa, gelatinosa et dilute flava immersis, 

 inordinatis ; contentu dilutissime caeruleo-viridi centro hyalino ; mul- 

 tiplieatione vegetabili; partitionibus cellularum in directionibus 

 omnibus. 



Colonies forming tubercular masses of indefinite shape and size ; 

 cells angular, 0.8-1.2/j, diam., slightly longer than the diameter, 

 embedded in a dense, copious, gelatinous matrix of light yellow color, 

 arranged in no definite manner; contents very pale blue-green with 

 hyaline center ; reproduction vegetative ; cell divisions in all directions. 



Growing on Rhodochorton Rothii in company with Dermocarpa 

 hemispherica and Dermocarpa suffvlta along high-tide level in shaded 

 places. Moss Beach, San Mateo County, California. 



Palmella conferta Kuetzing, Phyc. Germ., 1845, p. 149 ; Tab. Phyc. 

 1845-49, p. 12, pi. 16, fig. 4. Pleiirocapsa conferta (Kuetz.) Setchell, 

 Alg. nov., 1912, p, 229. 



