{901 | GAMETOGENESIS AND FERTILIZATION IN ALBUGO 161 
of germination. It matters not that in one instance it is before 
and in the other after the resting period. The divisions which 
in primitive multinucleate forms come after the resting period 
have in A. candida and A. Tragopogonis been transferred to a 
time before the winter rest. The condition is very similar to 
that presented in the spermatophytes, where intraseminal ger- 
mination immediately following fertilization is the rule, although 
many orchids retain their one-celled condition indefinitely. 
Although the division of the fusion nucleus is the first step 
in germination, the time of this mitosis is subject to variation 
in different types. The division is delayed in the forms of 
Albugo having multinucleate oospheres, in Peronospora parasitica 
(Wager 1900), in Saprolegnia and Achlya (Trow 1895 and 
1899). The division occurs soon after fusion in species of 
Albugo having uninucleate oospheres, and in the Peronospo- 
raceae (Berlese 1898). It appears from the consideration of 
these species that it is not simply a disproportion between the 
volume of the cytoplasm and the number of nuclei that induces 
division, for this disproportion is as great in the case of Perono- 
spora parasitica, Achlya, and Saprolegnia, as in A. 77 ragopogonis. 
Wager (1900) has already indicated that in these species, in 
which the retardation of the fusion is most marked, the incep- 
tion of division is also most delayed. He says (pp. 275-276): 
Peronospora parasitica is at St the only member of the group with 
retarded nuclear fusion. . . . - this species it is delayed until the thick 
zygote membrane has been oe formed. The ripe oospore of P. parasitica 
is uninucleate. . .. . In all the other species of Peronospora which have 
been examined the ripe zygote is multinucleate. 
Similarly, Trow (1895, p. 648, and 1899, p. 175) finds that 
fusion is slow in Achlya and Saprolegnia, and likewise the 
division of the fusion nucleus does not occur until after the 
oospore has passed the resting period. This association of 
retardation in fusion with delay in division suggests that after 
the act of fusion is completed, so far as the microscope can give 
evidence, there may be further changes which the elements of 
the pronuclei must undergo before fusion is really completed. 
