CYLINDROSPORIUM ON STONE FRUITS 
167 
Salmon (24) ) ; but even here the host tissue is not killed. In this 
respect Cylindrosporium resembles the last named species, and the 
presence of haustoria here is probably related to this behavior. 
The formation of spermatia-like bodies in connection with struc- 
tures which appear to be homologous with the ascogonial branches of 
the Collemaceae is also very interesting. The function of these bodies 
is not known. Several attempts to germinate them have always re- 
sulted in failure, but considering the difficulty of germinating the 
normal conidia this is not a very strong argument in favor of their 
spermatial nature. Their position on the surface of the stroma with 
the trichogyne of the ascogonium (?) projecting among them would 
certainly facilitate fertilization, if they do now function or have ever 
functioned as sexual organs. The most nearly similar arrangement 
is found in species of Physma. Here there are several ascogonial 
branches arising in the base of the spermogonium, as in Coccomyces on 
stone fruits, but passing around the spermogonium to the surface of 
the thallus. See Stahl (27), Sturgis (28), and others. 
The ascogonial structures found in Gnomonia erythro stoma have 
been studied by Brooks (6) and were not found to function as female 
sexual organs. On the contrary he thinks the ascogenous hyphae 
arise from vegetative cells. A similar condition was found in Poly- 
stigma rubrum by Blackman and Wellsford (5). From analogy and 
from the fact that the ascogonial structures appear to disintegrate 
in many cases, one is led to think that in Coccomyces also the asco- 
gonium does not function as a sexual organ. However the fact that 
the ascogenous hyphae arise from several points similarly situated in 
the ascocarp indicates that at least a part of the structure may function 
as an ascogonium. 
Control Measures 
Now that the complete life history of the fungus is known, it should 
be much easier to devise methods for controlling the disease. Since 
it lives over winter in the dead leaves it is very important that leaves 
from trees which are infested with the disease be raked together and 
burned or buried. If all such diseased leaves are destroyed in and near 
the cherry orchard there is little danger of the disease appearing the 
following season in such abundance as to be of a serious nature. 
If for any reason destruction of the diseased leaves is not feasible 
or desirable and one must depend on sprays to keep the disease in 
check, the spraying should begin early, at least by the middle of May. 
