18 BOTANICAL GAZETTE [JULY 
no particular thickening of the wall, divides successively and “ 
rise to all of the subsequent structures. The general morpho < 
of the sporeling in its subsequent development (fig 19) is like t ¢ 
of the fertilized female gamete. The late development of t ' 
sporeling was followed up to the stage consisting of about 100 cells. 
The sporeling at this stage is a filamentous structure whose Sate 
morphological character is hard to distinguish from the filamentous 
product of the fertilized gametes. Whether the products of the 
apogamous sporelings would reach maturity is not yet determined. 
Mitosis in the vegetative cells of zoospore-producing plants 
Zoospore-producing plants of Zanardinia, in their external 
morphology, do not differ from gamete-producing plants except in 
their reproductive organs. The general morphology of the cells 
composing the thallus is alike in zoospore-producing and gamete- 
producing plants. The size of the cells in the superficial layers, 
where the reproductive organs originate, was measured in both 
plants and was found to be the same. 
Vegetative mitosis was studied in the cells of young plants 
1.5 cm. in diameter, and in older 
The cells of the hairs upon the margin of the adult plants were 
also favorable for the st 
udy of vegetative mitosis, 
The size of the resting nucleus in the superficial cells is about 
the plastids or is even smaller. That the 
represented chiefly by a number of irregular 
y staining globules attached to the outside 
gradually diminish as the quantity of the 
thin increases, that centrosome-like structures 
knots, that the deepl 
of the membrane 
chromatin knots wi 
» Was the appearance of 44 chromosomes, which — 
were counted accurat 
phase and anaphase. 
: On account of the cell organization, the zoospore-forming 
individual of Zanardinia cannot be considered as the homologue 

plants 7 or 8cm. in diameter. | | 
fe 


