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tion of pycnidia gradually ceases, and is replaced by the development 
of peritbecia ; this occurs independently of the time of year, only re¬ 
quiring a sufficient amount of moisture. Moreover, only the feebly- 
developed stages of the Cytispora are found in the open air, and no pe- 
rithecia at all. 
The peritbecia first appear at the base and are most numerous in the 
center of the stroma, while the pycnidia occupy the circumference. 
The first beginnings of the peritbecia consist of small, globose knots 
of hyphse, plainly visible on account of their greater transparency, 
which distinguishes them from the darker stroma. They are clothed 
on the outside by a layer of fine, delicate, brownish liyphae, which are 
more or less parallel and run in the direction of the axis. The kuots 
themselves consist of pseudo-parenchyma, whose cells are small and thin- 
walled but stronger than those of the outer layer. In what follows, the 
latter will be designated as the outer and the former as the inner peri- 
thecium wall. Within this pseudo-parenchyma an organ has been twice 
observed which might be called u Woronin’s hypha” or perhaps an u as- 
cogonium.” In the first or younger stage it was, as compared with the 
surrounding tissue, a spirally coiled hypha with two turns and filled with 
dense protoplasm, which distinguished it clearly from its surroundings. 
The second case observed was of an older stage. The mass of tissue 
forming the young pycnidium was larger, but its structure was essen¬ 
tially the same. In this case the place of the pseudo-parenchyma was 
nearly filled up by a large coarse hypha which was wound up into a 
knot. It was no longer a simple spiral, but had a more complicated 
form. As far as could be made out it consisted of two or three coils, 
lying one within another, with simple ones at both the top and bottom. 
Here, too, the cell contents were denser than in the surrounding tissues. 
In this case some few cells were especially prominent on account of their 
size, but it could not be decided whether or not they were connected 
with the large hyphra or were the beginnings of future asci. 
In spite of a continued search we failed to observe any other stages. 
It is difficult to hit upon just the right stages of development, for thin 
sections of these stromata are not easily made, and the hyplme in ques¬ 
tion may not always be so well developed. It therefore remains to be 
seen whether this hypha is directly connected with the formation of 
the asci; that is, whether it is an aseogonium or Woronin’s hypha. 
In older stages the circumference of the perithecium is considerably 
larger. A very rapid growth takes place at the apex, forming a peri¬ 
thecium neck which penetrates the stroma. The neck is for a long time 
of nearly the same diameter as the perithecium, and it is not until it pro¬ 
jects above the stroma that the lower portion increases in circumfer¬ 
ence. The differentiation of tissues observed in the earliest stages can 
also be seen later on. The outer wall, whose liyphm in the meantime 
have become coarser and browner, surrounds the entire reproductive 
body, and the neck is formed from it. It is composed of liyphae which 
