Pirozynskiella S. Hughes, Mycologia 99(4): 632 (2007).
Index Fungorum number: IF 505762; Facesoffungi number: FoF 12637, 3 morphological species (Species Fungorum 2022), 1 species with molecular data.
Colonies on the natural substrate hairy, brown, growing on the upper leaf surface. Sexual morph: Unknown. Asexual morph: Mycelium partly superficial and partly immersed, consisting of branched, septate, brownish, smooth- to rough-walled hyphae, 2–3 μm wide. Conidiophores semi-macronematous or micronematous, erect, cylindrical, brown, smooth-walled. Conidiogenous cells holoblastic, integrated, terminal, and cylindrical. Conidia in unbranched acropetal chains, dry, 1–3-septate, subcylindrical to cylindrical, tapering toward both ends, brown to pale brown, verruculose (adapted from Hernandez-Restrepo et al. 2017).
Type species: Pirozynskiella solaninum (Sacc. & P. Syd.) S. Hughes
Notes: Pirozynskiella is characterised by superficial and partly immersed mycelium, semi-macronematous or micronematous, erect, cylindrical, brown conidiophores, and 1–3-septate, subcylindrical to cylindrical conidia. Hernandez-Restrepo et al. (2017) added P. laurisilvatica which differs from the type species P. solaninum in having verrucose conidia. No phylogenetic study has been done on Pirozynskiella. Pirozynskiella morphologically resembles Heteroconium but can be differentiated based on its fungicolous nature and conidial septation during maturity. The conidia in Pirozynskiella initially have a central septum which turns centrifugal or intercalary on maturity whereas in Heteroconium the septum is formed at the base of the conidium with other septa formed from the base to the apex (Hughes 2007; Hernandez-Restrepo et al. 2017). The taxonomic placement of Pirozynskiella is doubtful as sequence data is available for only one species and is currently in Asterinales genera incertae sedis. More collections with DNA sequence data are needed to confirm the taxonomic placement of Pirozynskiella. Molecular markers available for Pirozynskiella are ITS and LSU.