494 BOTANICAL GAZETTE [JUNE 
from a subhymenial layer. This seems reasonable, since at this 
stage the compact wall of the perithecium is an unlikely place for 
new growth, and there is no evidence of new hyphae being found 
to account for the paraphyses in other forms. It seems very prob- 
able that this is their origin here. 
Summary 
1. The stroma is differentiated into four regions, and in one of 
these further zonation is evident. 
2. The firm structure of the stroma is gained by various me- 
chanical devices for support, such as tubular extensions from cells, 
branching and intertwining of hyphae, and special articulation 
surfaces. 
3. The hyphae are differentiated into three types from the 
time of their emergence from the substratum: those that form the 
major part of the stroma, those that form the perithecia and Wo- 
ronin hyphae, and those that form the superficial layers and probably 
the conidiophores. 
4. The cells of the hyphae are originally binucleate, but may 
become multinucleate. 
5. The formation of the perithecia is initiated by the massing 
of the hyphae into a circular knot, within the center of which the 
Woronin hyphae differentiate. 
6. The ascogonia develop from the cells of the Woronin hyphae 
by rounding out, partially separating from each other, and increas- 
ing in size. 
7. The ascogonia do not drop to the bottom of the perithecium 
in the older stages, but come to lie comparatively closer to the 
bottom by an expansion of the perithecial wall toward the periphery 
of the stroma. 
8. The nuclear program within the ascogonia is one of few 
divisions and great increase in size, up to the stage where the 
ascogonia are well rounded out, and then of rapid division without 
the maintenance of size. 
9. The ascogonium buds out protuberances that are the begin- 
nings of the ascogenous hyphae. 
