Morphological variations in a new species of Entophlyctis. I. The species concept

Abstract

A new endobiotic fungus Entophlyctis variabilis is described. This fungus exhibits morphological variations which cut across recognized taxonomic lines. The relationship of the thallus to the substratum can be epi-endobiotic, interbiotic, or endobiotic. During thallus development, the wall of the encysted zoospore remains as a discharge tube, as an appendage on the zoosporangium, or as a part of the enlarging zoosporangium. These morphological variations result from three developmental patterns for zoosporangial differentiation. In type I development, the zoosporangium develops from the germ tube, and the cyst remains as a discharge tube. In type II development, the cyst is incorporated into a portion of the enlarging germ tube which becomes the zoosporangium. In type III development, the zoosporangium develops directly from the enlargement of the cyst. In each type of development, the zoosporangium develops from the region of the thallus where the nuclei are located.