214 BOTANICAL GAZETTE [Marcu 
other Ascomycetes are then laid down, and the dome cell thus 
cut off develops into the ascus. 
_ Ascus 
The young ascus increases rapidly in size, and pushes upward 
among the paraphyses. It assumes a definite cylindrical shape, 
and its two nuclei, now closely approximated at its center, soon 
fuse (fig. 23). Fusion nuclei containing two nucleoli are fre- 
quently found (figs. 22, 23). After fusion the nucleus increases in 
size as the ascus enlarges. The two nucleoli evidently fuse, the 
fusion nucleolus being larger and staining deeply. 
The chromatic material undergoes certain changes which call 
for special comment. The extrusion of chromatic bodies from the 
nucleus during synapsis or at early stages in meiosis is described 
by Dicsy (23) in Galtonia candicans, and by CARRUTHERS (14) in 
Helvella crispa. They state that these bodies may arise either from 
the nucleolus or nuclear framework. In both cases they are 
impregnated with chromatin. They are ejected forcibly through 
the nuclear membrane, and on escaping become definitely pyriform 
by constriction. They are sometimes drawn out behind into a 
fine thread and by means of this remain attached to the nucleus 
for a considerable time. Figures of these bodies given by CAR- 
RUTHERS resemble very closely similar bodies present in R. undulata. 
A comparison of the figures presented in the two cases shows them 
to be strikingly similar. However, the writer is unprepared to 
state that in R. undulata they actually represent ejected chromatin. 
It is certain that bodies taking the stain in a similar manner may 
be found in the cytoplasm of the ascus remote from the nucleus 
(figs. 22, 24, 2 
The mature ascus of R. undulata contains 8 unicellular hyaline 
spores. No attempt has been made to study the method of cutting 
out of the spores, nor has any critical examination been given to the 
nuclear divisions in the ascus. 
General considerations 
It is not necessary to review here the history of the development 
of our knowledge of the sexuality of the Ascomycetes. This task 
has been thoroughly accomplished by other workers. The earlier 
