Wiesneriomyces Koord., Verh. K. Akad. Wet., tweede sect. 13(4): 246 (1907).
Index Fungorum number: IF 10438; Facesoffungi number: FoF 06312, 3 morphological species (Species Fungorum 2022), 2 species with molecular data.
Saprobic on host. Sexual morph: Unknown. Asexual morph: Colonies effuse, comprising scattered conidiomata. Mycelium immersed. Conidiomata sporodochial, solitary to gregarious, setose. Setae subulate, septate, pigmented, thick-walled, arising from basal pseudoparenchymatous stalk or mycelium immersed in the substrata. Conidiophores macronematous, septate, branched. Conidiogenous cells holoblastic, discrete, determinate, terminate, clavate to cylindrical. Conidia hyaline but greenish, yellowish, or whitish in mass, non-septate; the conidium at each end of a chain tapered, intermediate ones more or less cylindrical, formed in uniseriate, acropetal chains and connected by narrow isthmi (adapted from Suetrong et al. 2014).
Type species: Wiesneriomyces laurinus (Tassi) P.M. Kirk.
Notes: Wiesneriomyces is characterised by sporodochial, solitary to gregarious conidiomata, macronematous, septate, branched conidiophores, holoblastic, discrete, determinate, terminal, clavate to cylindrical conidiogenous cells and hyaline conidia formed in acropetal chains and connected by narrow isthmi. Clements and Shear (1931) mentioned Chaetosira Clem. for W. javanica. Bisby (1949) did not agree and reported that Chaetosira was an invalid change and Wiesneriomyces is valid based on priority of the generic name. Matsushima (1971) and Pirozynski (1972) considered Gliophragma as a synonym of Wiesneriomyces. Kirk (1984) proposed the combination Wiesneriomyces laurinus based on the holotype of Volutellaria laurina, reported the species is not congeneric with the type species of Volutellaria, V. acaroides based on the conidial morphology and showed that Volutellaria laurina was an earlier name for Wiesneriomyces javanicus. Kuthubutheen and Nawawi (1988) added W. conjunctosporus found on submerged leaf litter from Malaysia. Suetrong et al. (2014) collected W. laurinus and W. conjunctosporus from Thailand and confirmed the phylogenetic placement of Wiesneriomyces based on SSU and LSU multigene analysis of 13 strains of Wiesneriomyces. Wiesneriomyces laurinus differs from W. conjunctosporus in having smaller setae, conidiomata and conidia and longer conidial chains (Kuthubutheen and Nawawi 1988). Suetrong et al. (2014) reported that the measurements of the two species overlapped and the most distinct morphological character to differentiate the two taxa are the structure of the conidiomata. Wiesneriomyces laurinus has more conspicuous sporodochia with conidiophores and setae arising from its basal, pseudoparenchymatous stalk while those of W. conjunctosporous are less visible and encircled by a single row of setae which arise from the immersed mycelium. Wiesneriomyces resembles Abgliophragma in having setose, pigmented sporodochia, conidiophores and isthmospores (Suetrong et al. 2014). Wiesneriomyces differs from Gliophragma in having smaller setae on the synnemata. Wiesneriomyces differs from Phalangispora in having branched chains of conidia. Wiesneriomyces is morphologically and phylogenetically a distinct and type species of Wiesneriomycetaceae. Molecular markers available for Wiesneriomyces include ITS, LSU, SSU, TEF-1 and RPB2.