New York AGRICULTURAL EXPERIMENT Station. 337 
On the other hand it is evident that Schizophyllum commune Fr. 
cannot penetrate living apple-tree bark and it is quite probable 
that the same is true of pear-tree bark. The result of the inocu- 
lations on the quince cannot be regarded as conclusive because 
of the small number of inoculations made; but numerous inocu- 
lations made in the spring of 1899 showed that the dark spored 
fungus can produce a cankered condition of quince hmbs when 
inserted under the bark. 
The stress of other duties during the growing season prevented 
any study into the nature of the canker fungus and nothing further 
was done until fall when cultures of the fungus were shown to 
Mr. F. C. Stewart, the Station Botanist. He at once noted a 
strong resemblance of the dark spores to those of the black rot of 
the apple, Sphaeropsis malorum Pk., and suggested that it might 
be that disease. Mature apples were at once inoculated with 
material from the test tube cultures that had been obtained from 
cankered apple-tree limbs. In twenty-four hours decay had be- 
gun around the points of inoculation and in sixteen days pyc- 
nidia and mature spores of Sphaeropsis were found on all inocu- 
lated apples. The check apples which were punctured but not 
inoculated and kept. under the same conditions remained sound. 
This experiment was repeated many times and the results were 
always the same. 
Now that it was known what to look for an examination of 
cankered limbs in the orchard revealed the presence of an abun- 
dance of small, dark, fungus pustules or pyenidia on the brown 
and shrunken areas of dead bark. Fig. 3 of Plate XXVIII is a 
larger view of the smaller canker shown in Fig 1 at 0. An ex- 
amination of the bark on the older portion of the cankered area 
reveals the presence of numerous pycnidia in which the dark col- 
ored spores, that have been frequently mentioned, are borne. 
They are shown natural size in Fig. 4, which is a small section of 
the dead bark from the same canker. It will be seen that the 
pycnidia are abundant and large enough to be easily found. 
22 
