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THE PYCNIDIUM OF CICINNOBOLUS. 
J. M. VAn Hook. 
The occurrence of Cicinnobolus as a parasite, for the most part on the 
powdery mildews. has been well known since the genus was established in 
1853 ; however, there seems to have been more interest in forming new spe- 
cies rather than noting the various forms, many of which are doubtless 
caused by the specific parts of the host attacked, their shape determining 
the shape of the pycnidium of the parasite. For example, when a conidi- 
ophore of a host is converted into a pyenidium it is entirely different in 
shape and size from one formed from a perithecium of a host. 
Many species of this genus are now described, most of these being named 
from the host of the powdery mildew rather than from the host of the 
Cicinnobolus. From what is already known of the wide variation of the 
fruiting forms of these parasites, together with the similarity of descrip- 
tion of many of their essential parts, much confusion of species has doubt- 
less been made. It is hoped that critical study of seasonal variation of the 
parasite upon a single powdery mildew host will be made in the future 
along the lines of Griffiths (The Common Parasite of the Powdery Mil- 
dews. Bull. Torr. Bot. Club, 26, 1899.). 
Most species have been described as parasitizing the mycelium or conidi- 
ophores of their hosts; however, in at least three cases they are reported 
on perithecia. These are by Griffiths on Erysiphe cichoracearum DC., by 
Saceardo and Sydow on Unecinula salicis (DC.) Winter and by Cocconi on 
Phylactinia corylea (Pers.) Karst. It is not strange that the last two 
should have been originally called respectively a Phoma and a Phyllosticta. 
So far as the writer can learn, the Cicinnobolus herein mentioned has not 
previously been reported on the mycelium, conidiophore or perithecium of 
Podosphaera oxycanthe (DC.) de Bary. 
The present brief paper is to show a form exceedingly common on the 
powdery mildew of cherry, here in Monroe County, Indiana. This seems 
to form fruit only in the perithecia of the host and usually at about the 
same stage of its maturity. In figures 1 and 2 of the accompanying plate, 
the comparative forms of the attacked and unattacked perithecia are shown. 
These figures represent a fair average of a large number examined and 
measured. It will be observed that parasitized fruit bodies are slightly 
smaller and have only slightly less developed appendages. Attention is 
always attracted by the presence of conidia instead of asci when the peri- 
thecia are crushed, though a more critical examination of the exterior will 
enable one to judge when pycnidia are present. 
These parasites are an extremely interesting and attractive group from 
an economic view as well as from a morphological one. There has always 
appeared to be a possibility of their employment to hold certain of the most 
dangerous powdery mildews in check. 
It would also be an interesting problem to determine the exact relation of 
the pyenidium of the Cicinnobolus to the perithecium of the host by means 
of a critical study of stained sections made from material such as was used 
in making the accompanying figures. 
