Pseudo-Pleurococcus, Nov. gen. 
BY 
JULIA W. SNOW, Ph.D, 
With Plate XI. 
JDLEUROCOCCUS VULGARIS, though oneofthe most 
common of all Algae and one that has received much 
attention, is also one about which there still exist widely 
differing views. 
Klebs (5), Artari (1), and Gay (4) hold that Pleurococcus 
vulgaris is a perfectly constant form which reproduces only 
by means of vegetative division, and either exists as single 
cells or forms small cell-complexes more or less quadrangular 
in shape. This, according to these authors, is accidental, 
and division in other directions soon occurs, producing the 
normal small complexes. 
Chodat (3), on the other hand, states that ‘ Pletirococcus 
in the various conditions of its evolution may develop 
branches, filaments, sporangia with zoospores, gametes, and 
spores.’ And under the name of Pleurococcus he would 
include f not only the common form without a pyrenoid, but 
also the similar one with a pyrenoid {PL simplex, Artari), as 
well as such very different forms as Cystococcus and Proto- 
coccus vulgaris .’ Further, he regards Pleurococcus as one of 
the Chaetophoraceae in a stage of degradation, owing to its 
existence as a Lichen-gonidium. 
[Annals of Botany, Vol. XIII. No. L. June, 1899.] 
O 
