368 CONNECTICUT EXPERIMENT STATION REPORT, I912. 
of the summer spores is practically over. It is quite unlike 
the Cytospora stage in that the spores are borne in sacs, or 
asci, situated in special receptacles called perithecia. 
The mature perithecia, Plate XXVIII k, are minute, light to 
dark-colored spherical bodies, situated within, but generally 
beneath and around, the edge of the pustules. By means of 
long black necks these perithecia open on the exposed surface 
of the fruiting pustules, where they show as minute black 
specks called ostioles. With the later growth and wearing away 
of the fruiting pustules these ostioles sometimes project as 
short spines. Each perithecium contains numerous, hyaline, 
oblong, asci, Plate XXVIII f, tapering somewhat at their base, 
within which are eight ascospores arranged one above another 
in one or two rows. In size the asci usually vary from 4o to 
45 » in length by 7 to 9 » wide, though some vary from 37 to 50 » 
in length. 
The ascospores, Plate XXVIIIc, are hyaline, oblong to 
broadly oval, with a central septum, at which they are often 
slightly constricted. These spores are usually rounded at the 
ends, though sometimes somewhat pointed at one or both ends. 
They vary from 6 to Io p in length by 2.75 to 5 » in width. 
While the chief time of germination of the ascospores is 
undoubtedly in the spring, their production and germination 
seems to be more or less distributed throughout the year. After 
rainy weather they are shot through the ostioles of the perithecia 
with some little force, and no doubt may be carried much 
further by the wind. By this means their distribution is greatly 
facilitated, and, because of their greater vigor, some experi- 
menters believe they are more important in producing infection 
than the conidial spores. 
Progress of Disease. From our inoculation experiments it is 
evident that seedling trees one-half inch or less in diameter 
may be girdled, and in some cases their tops killed in one 
season, Plate XXV a. Sprouts an inch or more in diameter may 
likewise be entirely girdled for a distance of six or more inches, 
so that the death of the parts may be expected at least by the 
following spring. We have not inoculated the large limbs of 
trees, neither have we measured the rate of growth of cankers 
on the same, but we have had under general observation, for 
several seasons, marked trees at both Stamford and Middlebury. 
» 
