488 The Botanical Gazette. [November 
Pertthecia.—Perithecia, in all stages of development, may 
be found as early as the last of July, occurring in most cases 
rather evenly scattered over the parts covered by the myce- 
lium. Owing to the close interweaving of the mycelial fila- 
ments, it is difficult to make out clearly the changes which 
take place in the formation of the perithecia.* As a rule 
their development begins at the intersection of two or more 
mycelial threads. There is little regularity, however, in the 
matter, and nothing that could be looked upon as a sexual 
act. Usually short branches, with frequent septa (figs. 11 
and 12) grow out from the main hyphe. These twist around 
each other, forming a more or less close weft, globose in 
shape (figs. 13 and 14). At first the bodies are hyaline, but 
they soon show a brown tint and at the same time become 
more globular in shape. With increasing age the evidence 
of the short branches originating from the main hyphe dis- 
appears, and later the walls of the peritheciabe come clearly 
defined (figs. 15 and 16). Soon after this there is developed 
from the outer walls of the perithecium eight to thirty ap- 
pendages (fig. 16), which are at first hyaline and without 
septa, but later become brown near the base and divided by 
several cross walls. In the mature perithecia (figs. 17 and 18) 
the tips of the appendages are hooked and not unfrequently 
they are branched. The length of the appendages varies 
greatly, the form on Vitis vinifera from the Pacific coast 
(fig. 19) having especially long ones. Within the perithecia 
are found the ovate asci containing the spores. There are 
four to eight, rarely ten, asci in each perithecium, and from 
or more layers of colorless cells (fig. 20a), which in the early 
stages at least fit close around the asci, and in some cases seem 
to extend into the interstices between the latter. These cells 
take stains in the same manner as the asci. In all the material 
er many attempts to find satisfactory material for the study of the devel- 
opment of the perithecia, the best results were obtained by gently boiling for 
half a minute small fragments of leaves containing fertile hyphe and — 
: hecia easily separate from the leaf and the weft of fila- 
ments may be easily floated on a slide, stained, and studied, The most satis- 
1 
tory stain found was ordi : : J . 
volume of water, ‘nary red ink diluted with 10 to 25 per cen 
