Pithomyces Berk. & Broome, J. Linn. Soc. Bot. 14: 100 (1873).
Index Fungorum number: IF 9412; Facesoffungi number: FoF 03611, 43 morphological species (Species Fungorum 2022), 6 species with molecular data.
Saprobic or pathogenic on host. Colonies on substrate in the form of ascomata arising in groups of singles, black, erumpent with broken plant parts protruding from sides, conical, beaked, often intermixed with asexual morphic colonies which are effuse, cottony with yellow thick mat of aerial mycelium. Colonies on MEA dark brown with yellow slightly verruculose mycelia. Sexual morph: Upon section, ascomata unilocular, conical with thick peridium. Trabeculae often branched. Asci with ocular chamber, 8 spored, cylindrical pedicillate. Ascospores fusiform, light brown, 3-septate, constricted at middle septa. Asexual morph: Conidiophores mononematous, micronematous, mostly intercalary, sometimes deticulate, aseptate. Conidiogenous cells mono or polyblastic, rhexolytic, light brown, smooth, with broad conidial attachment. Conidia solitary, dry, dark brown to black, obovate to oblong, veruculose to spinolose, with 3–5 mostly longitudinal dark septa (adapted from Pratibha and Prabhugaonkar 2015).
Type species: Pithomyces flavus Berk. & Broome
Notes: Pithomyces is characterised by unilocular ascomata, trabeculate pseudoparaphyses, cylindrical pedicellate asci and fusiform, light brown, 3-septate ascospores, constricted at middle septa. The asexual morph is characterised by mononematous, micronematous, mostly intercalary conidiophores, mono- or polyblastic, rhexolytic, light brown conidiogenous cells, and dark brown to black, obovate to oblong, veruculose to spinolose conidia. Pratibha and Prabhugaonkar (2015) collected Pithomyces flavus together with the sexual morph of the fungus Astrosphaeriella vesuvius. Pratibha and Prabhugaonkar (2015) confirmed the sexual and asexual link by both morphological and molecular data and provided an epitype. The authors cultured and sequenced Astrosphaeriella vesuvius and showed that the taxon formed a distinct lineage in Astrosphaeriellaceae. Pratibha and Prabhugaonkar (2015) retained the name Pithomyces flavus over Astrosphaeriella vesuvius based on one fungus one name rule. Pithomyces was previously considered as the asexual morph of Leptosphaerulina (Wijayawardene et al. 2012; Pratibha and Prabhugaonkar 2015). Phookamsak et al. (2013) established Leptosphaerulina saccharicola to accommodate taxa characterised by the asexual morph similar to Pithomyces saccharicola and reported that P. chartarum (DS1bioJ1b) and P. valparadisiacus (CBS 113339) are not related to Leptosphaerulina based on phylogenetic analyses. Pratibha and Prabhugaonkar (2015) reported that Pithomyces flavus has phylogenetic affinity with Astrosphaeriella basal to Aigialaceae. Pithomyces is currently a distinct genus in Astrosphaeriellaceae but fresh collections are needed to confirm the natural placement of the genus. Molecular markers available for Pithomyces are LSU, SSU, ITS, BTUB, GAPDH, RPB2 and TEF-1.
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