VOLUME 7 JUNE 2021 Fungal Systematics and Evolution PAGES 177–196 doi.org/10.3114/fuse.2021.07.09 Taxonomy and phylogeny of the basidiomycetous hyphomycete genus Hormomyces J. Mack*, R.A. Assabgui, K.A. Seifert# Biodiversity (Mycology and Microbiology), Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A 0C6, Canada. #Current address: Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada. *Corresponding author:
[email protected] Abstract: The taxonomy of the genus Hormomyces, typified by Hormomyces aurantiacus, which based on circumstantial Key words: evidence was long assumed to be the hyphomycetous asexual morph of Tremella mesenterica (Tremellales, Tremellomycetes) Dacrymyces or occasionally Dacrymyces (Dacrymycetales, Dacrymycetes), is revised. Phylogenies based on the three nuc rDNA markers Oosporidium [internal transcribed spacers (ITS), 28S large ribosomal subunit nrDNA (28S) and 18S small ribosomal subunit nrDNA (18S)], Tremella based on cultures from Canada and the United States, suggest that the genus is synonymous with Tulasnella (Cantharellales, Tulasnella Agaricomycetes) rather than Tremella or Dacrymyces. Morphological studies of 38 fungarium specimens of Hormomyces, 1 new taxon including the type specimens of H. callorioides, H. fragiformis, H. paridiphilus and H. peniophorae and examination of the protologues of H. abieticola, H. aurantiacus and H. pezizoideus suggest that H. callorioides and H. fragiformis are conspecific with H. aurantiacus while the remaining species are unlikely to be related to Tulasnella. The conidial chains produced by H. aurantiacus are similar to monilioid cells of asexual morphs of Tulasnella species formerly referred to the genus Epulorhiza. The new combination Tulasnella aurantiaca is proposed and the species is redescribed, illustrated and compared with similar fungi.