Fungal Growth Response to Thermal Gradients in Convection Incubators

Abstract

There is obvious similarity between the urediniospores described and the characteristic aeciospores of the genus, especially in spore wall color and markings, and pore number and position. True peridial cells are not present but the stalked colorless cells described, but not designated, have thick hyaline walls and coarse sculpturing suggestive of peridial cells. These characters support a proposal that the uredinia have their origin in roestelia in spite of their parasitizing the telial host. The presence of the hyaline cells; the rare teliospores and presence of mesospores all indicate that the species is unstable and probably in a state of active evolution. Gaumann refers to and illustrates thick-walled urediniospores as amphispores and suggests them as a possible means of overwintering. These have not been seen in the Canadian material. The uredinia of G. gaeumannii ssp. albertensis are small and easily overlooked.