18 University of California Publications in Botany [Vol. 8 



to, if not identical with, the plant commonly associated with the same 

 host plant on botii the Atlantic and the Pacific coasts of the United 

 States. It is also nsnally aceonipaiiied by other species of Myxo- 

 phyceae. 



The genus ValmcUa, as now restricted, includes only forms of 

 Chlorophyceae, hence it was necessary to reject that generic name 

 and adopt another for this widel}' distributed plant which seems to 

 be on the border between the Bacteria and the Myxophyceae. Setchell 

 (1912. p. 229), with special reference to the larger cells, has referred 

 the plant of Kuetzing to Plcnrocapsa, but the smaller-celled plant is 

 not properlj' to be referred to that genus. Wille has created the genus 

 Chlorogloca to receive a plant yery similar to ours, and known as 

 Pahncllu ? tuberculosa Hansgirg (1892, p. 240) and this generic name, 

 Chlorogloca, is consequently adopted. 



Chlorogloea conferta differs from C. tuherculosa in the size of the 

 cells, in their arrangement, and in the number of planes of cell divi- 

 sions, C. tuherculosa dividing in but one plane according to Wille, 

 although it is difficult to understand just how the colony arises if this 

 be true. The other species of Myxophyceae found on the material of 

 Kuetzing 's type seems to be a species of Pleurocapsa, though being 

 immature it is not safe to attempt to place, it. Possibly this is the 

 plant which has been considered to be a form of P. anwthystca Rosen- 

 vinge (1893, p. 967). 



2. Chlorogloea lutea S. and G. 



Plate 2, fig. 1 



Colonies extremely variable in shape and size, spreading over the 

 surface of the host by cell divisions in two planes, divisions in the 

 third horizontal plane forming a cushion of cells up to lOOfx thick, 

 the cells at first being arranged more or less in vertical rows, but the 

 radial arrangement being soon destroyed by divisions in other planes, 

 the outer portion of the colony having cells arranged -in no definite 

 order ; by horizontal divisions certain cells from the lower side of the 

 colony penetrate into the host, forming crooked, branched filaments 

 increasing in length by apical growth ; cells of these filaments soon 

 begin to divide in other planes than horizontal, producing masses of 

 cells, encroaching on one another, and finally coalescing into a solid 

 mass in the central portion of the colony ; cells 0.9-1.5/a diam., angular, 

 nearly quadrate ; terminal cells penetrating the host, up to 4/a long ; 



