Home • Powellomyces hirtus BR81 v1.0
Powellomyces hirtus Barr81. Photo by Joyce E. Longcore.
Powellomyces hirtus Barr81. Photo by Joyce E. Longcore.

Powellomyces hirtus (Barr81) is an exogenously-developing chytrid species that has been the subject of many studies, including physiological examinations, ultrastructural comparisons, and taxonomic reevaluations. This isolate of the species, formerly known as Entophlyctis confervae-glomeratae, was cultured by Donald J. S. Barr from pine pollen baiting of a flower bed soil sample from the Central Experimental Farm, Ottawa, Ontario, Canada in 1970. Until that time, the majority of Entophlyctis species had been described from fungi that were parasites on green algae. Barr used isolate Barr81 as one of the subjects of an extensive examination of physiological requirements and preferences conducive to the culturing of E. confervae-glomeratae. In 1980, Barr segregated a portion of the Chytridiales into the Spizellomycetales, which possessed a unique suite of zoosporic ultrastructural characters. Based on ultrastructurally-examined species available at the time, and that had been collected from soil substrates, Entophlyctis, including E. confervae-glomeratae, was placed within the Spizellomycetales. In 1995, Joyce E. Longcore described a new species of Entophlyctis from a sample of aquatic plant matter, but this new species possessed zoosporic ultrastructural characters indicative of the Chytridiales. Longcore subsequently returned the algal-associated Entophlyctis species, and the genus itself, back into the Chytridiales. Thus, Entophlyctis-like species from soil and with Spizellomycetales ultrastructure, including E. confervae-glomeratae, were reclassified into the new genus Powellomyces, named after chytrid researcher Martha J. Powell, in honor of her work on the ultrastructural features of this newly-reclassified group and additional chytrid taxa. Powellomyces hirtus is now the monotypic species of the genus, which has been further reclassified based on additional ultrastructural and phylogenetic study. The wealth of information on P. hirtus Barr81, the isolate’s continued viability, and its relative ease of culturing makes this a valuable research organism.