Jolivette—Spore Formation. 1173 
plasm near the pole. According to the hypothesis that the 
centrosome is the seat of fermentative activities, as suggested by 
Harper (25 page 274) Fraser (16) holds that the centrosome 
as it pushes outward through the cytoplasm at the end of the 
third division might be regarded as constantly generating a fer¬ 
ment. This ferment would flow back in the wake of the centro¬ 
some and would produce a chemical change in the area through 
which it was distributed. Its effect would be* limited in certain 
directions by the presence of vacuoles and the ascus wall. 
Fraser (16) concludes that, whether the changes which take 
place in the cytoplasm are or are not due to enzyme activity, the 
main factor in the delimitation of the spore is an alteration in 
the cytoplasm originating at the centrosome and essentially simi¬ 
lar in character to that which produces the aster. 
The asci in Geoglossum glabrum Pers. have been found to be 
very favorable material for the study of spore formation and the 
following description is based on an extended study of the asci 
of this species. The material was fixed in the field in Flem¬ 
ing’s weak and Fleming’s medium solutions. The sections 
were cut five microns thick and stained with the triple stain. A 
large number of stages in spore formation can of course be ob¬ 
tained from a single ascocarp. I shall not now describe the 
formation of the ascus but proceed at once to the stages of nu¬ 
clear division and spore formation. When about mature the 
ascus is of the ordinary type but the wall at the apex is a con¬ 
spicuous lens shaped mass. In the one-nucleated stage the nu¬ 
cleus usually lies near one side of the ascus and about forty to 
fifty microns from the top. The cytoplasm is rather dense in 
the wall layer surrounding the nucleus while that in the re¬ 
mainder of the ascus, is greatly vacuolated consisting largely of 
strands running in from the periphery in various directions and 
often to the mass about the nucleus. The denser spore plasm at 
this stage does not fill the complete cross section of the ascus in 
the neighborhood of the nucleus as it does in so many other 
forms. 
While in this position the nucleus divides. Examples of the 
equatorial plate stages are comparatively abundant. Figure 1 
