4 University of California Puhlications in Botany [Vol.8 



to be seen between the vegetative conditions of certain unicellular 

 forms of Myxophyceae and those of Chlorophyceae. A much closer 

 resemblance is seen to be with various forms of the Schizomycetes or 

 Bacteria, so close, in fact, that it is often difficult to decide whether 

 a given cell or filament ought to be assigned rather to the one or to 

 the other group. Yet there are differences, as West has clearly 

 pointed out (1916, pp. 38, 39). It has been the custom, however, to 

 group the Myxophyceae and Schizomycetes together in a group by 

 themselves which Cohn has designated as the Schizophyta. 



Key to the Orders 



1. Vegetative multiplication by single cells (coccogonia) : unicellular forms either 

 single or in larger or smaller globular or irregular colonies, seldom filamentous.... 

 Order 1. Coccogonales (p. 4) 



1. Vegetative multiplication by groups of two to many cells (hormogonia); multi- 

 cellular forms, distinctly filamentous Order 2. Hormogonales (p. 51) 



Order 1. COCCOGONALES atkinson 



Thallus unicellular, associated into loose, more or less gelatinous 

 families, or occasionally' pluricellular, free floating or attached ; multi- 

 plication by direct cell divisions or by division of specialized cells 

 (gonidangia) into few to many small, non-motile cells (gonidia), or 

 by both. 



Atkinson, A college text book of Botany, 2d ed., 1905. p. 163. 



Coccogoneae Thuret, Essai Class. Nost., 1875, p. 377. 



Thuret {loc. cit.) was the first to emphasize the distinction between 

 the two groups of Myxophyceae, or Nostoehinees, as he designated 

 them. The Coccogoneae were distinguished from the Hormogoneae 

 (Thuret, loc. dt.) merely by name without further definite statement. 

 In 1886 Bornet and Flahault (p. 323) stated that the separation 

 between the two groups w^as made on account of their method of mul- 

 tiplication but without stating the exact nature of the method. The 

 group was first definitely characterized by Kirchner (1898, p. 50) and 

 it was defined again by West somewhat later (1916, p. 40) . The proper 

 distinction is that vegetative reproduction may take place by single 

 cells (coccogonia) instead of by short rows of cells (hormogonia) and 

 in general the members of this group may be distinguished as being 

 unicellular (or in non-filamentous colonies) instead of being properly 

 filamentous. 



