CYLINDROSPORIUM ON STONE FRUITS 
169 
6. The microconidia are not prodaced in pycnidial structures, as 
reported by Arthur (4) and by Pammel (22), but on the surface of 
the conidial stroma. 
7. While the microconidia (spermatia?) are being formed on the 
surface of the stroma, ascogonia-like structures are formed with their 
free end (trichogyne?) projecting above the surface. If these struc- 
tures do now function or have ever functioned as sexual organs, 
their formation at the same time and on the same stroma would make 
fertilization more certain. 
8. The fungus passes the winter as a stroma-like body in the fallen 
leaves, which in the early spring develops into an apothecium of the 
Phacidiaceous type. 
9. That the ascocarps are genetically connected with Cylindro- 
sporium has been shown by their continuous development from the 
stromata of Cylindrosporium, and by producing infection and Cylin- 
drosporium acervuli in living leaves when inoculated with ascospores 
from leaves, or with conidia from pure cultures from these ascospores. 
10. The forms of Coccomyces found on the eight species of Prunus 
fall naturally into three species, one on each of three more or less 
natural subdivisions of the host genus. 
The study on which this article is based has been carried on in the 
Botanical Laboratory of Cornell University under the direction of 
Prof. Geo. F. Atkinson, whom I wish to thank for many helpful sugges- 
tions and criticisms. Acknowledgments are also due Prof. W. D. 
Bancroft for some valuable suggestions. Prof. J. G. Hall for material 
collected at Clemson College, S. C, the Geneva Agricultural Station, 
the J. B. Stewart Nursery Co., and the Greening Nursery Co., for 
plum and cherry trees contributed for experimental purposes. 
BIBLIOGRAPHY OF PAPERS CITED 
1. Aderholdt, R. Uber die Spriih- und Diirrfleckenkrankheiten {syn. Schusslocker- 
krankheiten) des Steinobstes. Landw. Jahrb. 30: 771-830, pi. 18. 1901. 
2. Armstrong, H. E. and E. F. The origin of osmotic effects. III. The function 
of hormones in stimulating enzymatic change in relation to narcosis and the 
phenomenon of degeneration and regenerative change in living structures. 
Proc. Roy. Soc. (London) ser. B. 82: 588-602. 1910. 
3. The function of hormones in regulating metaboHsm. Ann. Bot. 25^: 
507-519. 191 1. 
4. Arthur, J. C. Plum leaf fungus. N. Y. Agr. Exp. Sta. Kept. 5: 293-298, 
figs. 6-10, 1886. Idem 6: 347, 348. 1887. 
