Ilo BOTANICAL GAZETTE [ FEBRUARY 
enough negative evidence had been secured to justify our con- 
sidering Uroglena as being among those forms which have no 
sexual mode of reproduction. It is certain that up to the present 
time nothing has been observed that can in any way be consid- 
ered as indicating anything but the simplest methods of multipli- 
cation. Kent (5) observed bodies which he designated as ‘‘ micro- 
spores’’ and ‘‘macrospores,’’ but that is the most that can be said 
in regard tothe fact. Zacharias (7) calls attention to larger cells 
in the periphery of the ccenobium, containing two red spots and 
two chromatophores, which he names ‘‘zygote formers.’’ Since 
he does not describe the process of conjugation, one is led to 
believe that it had not been observed and, for the present at least, 
the term zygospore will have to be classed with the microspores 
and macrospores of Kent. It naturally occurs to one that the 
so called zygote forming cells of Zacharias were merely ordinary 
individual cells about ready to begin the process of division. 
It would seem, then, since the only known method of repro- 
duction is by simple division, that the taxonomic position of 
Uroglena, if it is to be regarded as a plant, must be among the 
multicellular Chrysomonadacez of the class Syngenetice. 
It is so placed by Warming (8), and more recently by E. 
Lemmermann (9g), and while the charactegs of the genus are 
hardly in accord with the family Syngenetice as defined by 
Rostafinski, still it would seem that under the generally accepted 
idea of the Chrysomonadacee Uroglena would find a place in 
that order, together with Syncrypta. 
From the foregoing account it will be seenthat U. Americana 
varies decidedly from the description of U. volvex as given by 
Ehrenberg, Zacharias, and others. The fact that the European 
species is found most abundantly during the summer, while here 
the colder months are more favorable to its growth, may account 
for some of the minor variations. It seems probable, however, 
that what has been considered U. volvox by previous observers 
has not always been the same species, and that much of the ina- 
bility to agree, and the surprise expressed | ed more Fecent writers 
by a) 
that certain structures had 1 not b 5€ former 
