440 
B. B. HIGGINS 
the free end extends up to and often beyond the apex of the mass of hyphae, 
which by this time has broken through the leaf epidermis (figs. 6, 7). It is 
very much enlarged and coiled, usually making one complete turn, at the 
base; but it tapers gradually toward the free end into a very slender 
trichogyne. The trichogyne is generally erect, extending directly toward 
the apex of the young perithecium except where it is bent by pressure of 
the other hyphae. There is no distinct line of demarcation between the 
enlarged basal portion and the trichogyne. As the terms are used here, the 
"basal portion" includes only the part that is coiled, and all the erect 
portion is the "trichogyne." There are two comparatively large nuclei 
in the basal portion and two much smaller in the trichogyne (fig. 6). In 
some cases these nuclei are separated by cross walls; but the entire struc- 
ture, at this stage, takes the stain so evenly that it is extremely difficult to 
determine details of structure, and it is not possible to say at what stage the 
cross walls are formed. Observations indicate that they are laid down only 
after disintegration of the protoplasm has begun at the tip of the trichogyne. 
The protoplasm of the trichogyne soon becomes granular and dis- 
integrates, this process beginning at the tip. This continues until only 
about half the coiled basal portion remains. At this stage two healthy 
appearing nuclei remain lying close together in the remainder of the basal 
portion. This cell becomes the ascogonium and later on gives rise to the 
ascogenous hyphae. 
By the time disintegration of the trichogyne is completed, the cells of 
the surrounding hyphae composing the young perithecium have coalesced 
to form an almost solid mass of pseudoparenchyma ; but the perithecium 
continues to enlarge, apparently by formation of new cells over the surface. 
The perithecium soon reaches its full size. The outer cells develop thick, 
brown cell walls and become the permanent wall of the perithecium. The 
cells in the center remain thin-walled and colorless and are broken down 
by the later development of the asci (figs. 8, 9). 
Both the question as to the origin of the two nuclei in the ascogonium 
and the question as to their fusion must remain unsettled for the present. 
After a short rest the ascogonium becomes rapidly multinucleate. The 
nuclei are paired in the ascogonium and pass out in pairs into the ascogenous 
hyphae (fig. 8). Here they divide, one pair of the four resulting nuclei 
in each ascogenous hypha passing to the tip of the hypha, the other pair 
remaining in the base. A cross wall is now formed separating the two 
pairs of nuclei. The terminal cell enlarges and becomes the ascus. The 
two nuclei in the ascus soon fuse. The ascogenous hyphae apparently do 
not branch; and there is no crozier formation. Nearly all the cytoplasm 
of the ascogonium passes with the nuclei into the ascogenous hyphae, leaving 
the ascogonium almost empty and very difficult to distinguish; but in some 
cases its wall may yet be seen when the asci are nearly mature. 
This stage in the development of the young asci is reached early in the 
