Oedohysterium E. Boehm & C.L. Schoch, in Boehm et al., Stud. Mycol. 64: 59 (2009).
Index Fungorum number: IF 515421; Facesoffungi number: FoF 08060, 3 morphological species (Species Fungorum 2021), 2 species with molecular data.
Saprobic on host. Sexual morph: Hysterothecia isolated to gregarious, erumpent when young, superficial when mature, navicular, sometimes linear in more or less parallel rows, but non confluent laterally, or sometimes situated at angles, rarely flexuous or bifurcating, usually with obtuse ends, and with a prominent longitudinal slit. Sometimes, taller than wide, other times wider than tall. Peridium thick, carbonaceous, brittle with age, longitudinally striated on the margins, thickened towards base, less thick apically, composed of two to three distinct layers, the inner compressed and pallid, the outer thickened and pigmented. Pseudoparaphyses cellular, 1–2.5 μm wide, hyaline, septate, branched above, forming a usually pigmented epithecium above the asci. Asci cylindrical to clavate, usually short stipitate, and bitunicate. Ascospores irregularly biseriate in ascus, typically phragmospores, in one case dictyospores, curved, fusiform, with tapering apices, constricted at the median septum, with (4–)6–8(– 11) septa, at first hyaline-yellow, then pigmented sepia to brown at maturity. Genus characterized by a swollen or tumid supra-median cell, rarely with two cells swollen. Anamorph: Septonema (Adapted from Boehm et al. 2009).
Type species: Oedohysterium insidens (Schwein.) E. Boehm & C.L. Schoch
Notes: Oedohysterium was introduced by Boehm and Schoch (2009) with O. insidens as type species. Oedohysterium is characterized by erumpent hysterothecia, cylindrical to clavate asci and fusiform hyaline-yellow to brown ascospores. Oedohysterium insidens was previously known as Hysterium insidens but was not congeneric with the type species of Hysterium. Oedohysterium resembles Hysterium in having similar pigmented asymmetric phragmospores but differs in having enlarged supra-median cell (Boehm et al. 2009). Oedohysterium is phylogenetically distinct from Hysterium. Oedohysterium is morphologically and phylogenetically a distinct genus in Hysteriaceae.