Notes on the Morphology of the Genus Hemileia

SUMMARY

1.	A comparative study of the morphology of the sori in 32 species of Hemileia is presented. It is suggested that on the basis of soral morphology and position, the genus may be divided into subgenera. It is indicated that some named species may really be physiologic races.
2.	Pycnia and aecia are unknown. Negative results were obtained with cross inoculations of various unconnected aecia and with reciprocal inoculations using basidiospores from germinating teliospores of H. vastatrix.
3.	There are three types of sori found in the genus, the subepidermal, the superstomal “A,” and the superstomal “B.” The superstomal ‘A” type, with eighteen species, predominates. There are a few intermediate types.
4.	The importance of primary sori in the classification of rusts is stressed and support is given to the view that basal cells and teliospore variations are not sure bases for generic distinction.

The writer wishes to thank Dr. John A. Jump of the Department of Biology, University of Notre Dame, for his kind interest and encouragement during the course of this study.