Psathyloma Soop, J.A. Cooper & Dima, in Soop et al., Mycologia 108(2): 400 (2016)
Etymology: Derived from the generic names Psathyrella and Hebeloma (gender neuter).
Basidiomata agaricoid, terrestrial, pileus viscid, universal veil absent or fugacious, cortina absent. Basidiospores pale brown, ± ellipsoid, smooth, dextrinoid, with a germ pore. Cheilocystidia abundant, variable shape, thin-walled, hyaline. Pleurocystidia absent. Clamp connections present. Pileipellis an ixocutis.
Known distribution: South Pacific (Australia, New Zealand, and South America).
Index fungorum number: IF812051
Notes: Psathyloma forms a distinct clade separate from other genera of Hymenogastraceae. The genus is ectomycorrhizal and basidiomata are always found in Nothofagaceae forests fruiting on the forest floor. Psathyloma can be differentiated morphologically from Hebeloma by its smooth basidiospores with a large germ pore. Psathyloma and Hebeloma share similar macromorphology of the basidiomata; however, Psathyloma is typically smaller and more brittle than Hebeloma. The pileipellis composition is similar to that of Hebeloma. Psathyloma can be differentiated from Naucoria by their smooth basidiospores with a large germ pore as well as by the shape of the cheilocystidia. Moreover, Naucoria was not recorded with certainty from the native forests of New Zealand (Segedin and Pennycook 2001), presumably because of absence of their mycorrhizal hosts, mainly Alnus and Salix, in this region.
Type species: Psathyloma leucocarpum Soop, J.A. Cooper & Dima 2016, in Soop et al., Mycologia 108(2): 400 (2016)
Psathyloma catervatim Soop, J.A. Cooper & Dima 2016
Psathyloma leucocarpum Soop, J.A. Cooper & Dima 2016
Psathyloma psathyrelloides (Singer) Kuhar & Nouhra 2019
Soop, Karl & Dima, Bálint & Cooper, Jerry & Szarkándi, János & Papp, Tamás & Vágvölgyi, Csaba & G. Nagy, Laszlo. (2016). Psathyloma, a new genus in Hymenogastraceae described from New Zealand. Mycologia. 108. 10.3852/15-143.