162 BOTANICAL GAZETTE [SEPTEMBER 
The delay of division in species like Saprolegnia, P. parasitica, 
and Spirogyra (Chimelewsky 1888) may be due to a delay on 
the part of the nuclei in completely preparing for fusion, and 
to slowness in the act of fusion itself, an act which is not com- 
pleted when the mere fusion made visible by our present powers 
of magnification is effected. In this connection Wager (1899, 
p. 578) makes this suggestion: 
This difference in the behavior of the nucleus during the maturation of 
the oospore is probably connected with the mode of germination, DeBary 
has already pointed out that in Cystopus and some other species the oospore 
on germination produces at once a mass of zoospores. In Peronospora 
Valerianellae and others the oospore at once develops a germ-tube. It may 
be, therefore, that the uninucleate condition of the zygote indicates germina- 
tion by a germ-tube, and the multinucleate condition germination by the 
formation of zoospores. 
Apart from the relationships within the group which stand 
out with more or less clearness, the cytological phenomena 
emphasize strongly the affinity between the Albuginaceae, 
Peronosporaceae, and Saprolegniaceae. Peronospora parasitica, 
according to the research of Wager (1900), has a uninucleate 
oosphere, which is fertilized by the entrance of one antheridial 
nucleus. In oogenesis the nuclei divide simultaneously while 
passing to the periphery, as in Albugo, and then one returns to 
the ooplasm. A highly developed coenocentrum is present, 
and exerts an attractive influence upon the nuclei even as they 
lie in the periplasm. All of these conditions, together with the 
presence of the receptive papilla, clearly attest a relationship 
between the Albuginaceae and Peronosporaceae. The highly 
developed coenocentrum and the presence of a uninucleate 
oosphere indicate that the Peronosporaceae are the more highly 
developed group. Their ancestors may have been some forms 
possessing a uninucleate oosphere, similar to that of A. candida, 
from which one of the mitoses has later been suppressed as supet- 
fluous. Merely from the evidence of oogenesis, the Peronospo- 
raceae might be regarded as an offshoot from the Albuginaceae 
after the uninucleate condition had been attained; that is, they 
may represent a further development of the condition illustrated 
