Biological and Cultural Studies of Three Species of Protomyces

Abstract

Germination of chlamydospores of Protomyces inouyei, P. lactucae-debilis, and P. pachydermus was obtained in water at 20[degree]C after a resting period of about 7 months. The chlamydospore wall is 3-layered, consisting of a thick (5.5[mu]) , colorless, unsculptured epispore, and a very thin mesospore and endospore. At germination the outer walls rupture and the endospore emerges as the spore-sac. The granular cytoplasm is transformed into spores in the upper half of the sac and forcibly expelled. In P. pachydermus the spores fuse by twos either in the sacs or after expulsion and are connected by fusion tubes. Conjugation has also been observed in old cultures of this species. In culture these spores multiply by budding to form a yeast-like colony. Inoculation and reisolation experiments were successful. Cultural investigations indicate a relationship to the genus Taphrina.