Harper. — Cel l- Division in Sporangia and Asci. 487 
of generations from the original single nucleus of the proto- 
spore. It seems rather that the number of divisions in each 
spore depends on individual conditions of nutrition, & c., the 
same which determine the slight variability in size of the ripe 
spores. This is to be noted especially as showing that we 
have in the divisions of this spore-nucleus nothing directly 
comparable to the determinate number of divisions passed 
through by the ascus-nucleus to form the eight ascospore- 
nuclei. 
This period of nuclear multiplication is followed by the 
third stage, in which the spores ripen preparatory to being 
set free from the sporangium for distribution. In this stage 
they become for the first time enclosed in a true cell-wall. 
Through the preceding stages they have been mere naked 
bits of protoplasm bounded only by their plasma-mem- 
branes. Fig. 8 shows the spores when the wall first appears 
as a very delicate membrane which stains strongly with 
orange G. At first it is only to be detected in cases where 
slight plasmolysis has occurred in fixation, so that plasma- 
membrane and spore-wall are somewhat separated. Later it 
becomes much thicker and shows a double contour. With 
the formation of the spore-wall the protoplasm of its body 
undergoes contraction once more, and the spores which were 
closely pressed together and polygonal in outline during the 
period of nuclear division draw apart from each other and 
become more rounded in outline (Fig. 8). With these changes 
the spores are finally ripened and ready for dissemination. 
The spore germinates as a sporange. The stages of germina- 
tion consist in the breaking up of the multinucleated spore 
into a number of uninucleate swarm-spores. This may occur 
after a resting period in the case of 5. decipiens. In 5. 
Taraxaci , as is well known, the spores germinate to form 
swarm-spores at once. This formation of swarm-spores must 
be considered as a continuation of the stage of nuclear division 
in the spores which was interrupted by the ripening period. 
The whole may be roughly characterized as an embryonic 
stage in the life of the fungus. 
