Enpotui14 CANKER OF CHESTNUT 579 
connected. They are filled with dense protoplasm and contain more 
numerous and more prominent nuclei than do the cells of the envelope. 
The cells of the trichogyne resemble those of the ascogonium in every 
way except that they are narrower and are not curved nor so loosely 
connected. The trichogyne is apparently a useless organ in the formation 
of the perithecium. During the development of the latter it degenerates 
and disappears. 
The highest stage in the development of the ascogonium is shown in 
Fig. 93. From this time on it begins to degenerate. The dense pro- 
toplasmic content gradually becomes thinner, and later there are only 
ragged bridles of protoplasm across the lumen and irregular masses around 
the walls (Fig. 94) or else the entire contents draw up into a misshapen 
mass. But the behavior of the enveloping 
cells is quite the contrary. Their contents 
now become more dense, and their nuclei more - 
prominent and apparently more numerous. Up 
to this time the individual hyphe can be 
traced and open spaces are apparent between 
them; but now they have increased both in 
size and in number and have filled up the 
intervening spaces. They appear as a pseudo- 
parenchymatous tissue instead of as a coil of 
Fic. 94.— Cross section of 
hyphe. ; : the developing perithecium 
Before degeneration the ascogonia probably just as the ascogonial cells 
give rise to ascogenous hyphz, but these are ee Seale 
very quickly cut off by septa and are indistin- degenerate and the envelop- 
guishable among the enveloping hyphz. The be ean eee 
ascogonial cells are soon crowded out of shape pearance 
by the growth of the enveloping cells, and in 
later stages they appear only as misshapen masses wedged between the 
other cells. The whole primordium now increases rapidly in size and takes 
on the appearance shown in Fig. 9s. The beginning of the neck is shown 
at the top of the figure. Next, the wall is differentiated from the large- 
celled core. A cavity is formed by the breaking-down of some of the core 
cells, but is soon almost filled by paraphyses which arise from the bottom 
of the cavity (Fig. 88,.a, page 561). The young asci grow up between 
the paraphyses, arising from a system of hyphe which are presumably 
the continuation of the branches of the ascogonial cells. Eight bicellular 
spores are formed in each of the clavate asci. The hyphz that initiated 
the formation of the neck now push toward the surface, leaving a canal 
through the center (Fig. 88, b). Branches of these hyphe extend into 
the canal'to form the periphyses (Fig. 88, c). Meanwhile. the cavity 
