Herpotrichia Fuckel, Fungi rhenani exsic., suppl., fasc. 7 (nos 2101-2200): no. 2171 (1868).
Parasitic or saprobic on woody hosts in terrestrial habitats. Sexual morph: Ascomata scattered to gregarious, immersed, erumpent to nearly superficial, wall black, coriaceous, spreading on substrate as a subiculum, ostiolate, roughened. Ostiole single, central, flattened, papillate. Peridium thick at both sides and apex, basal wall thinner, 2-layered, outer layer composed of pigmented, thick-walled cells of textura angularis, inner layer comprising light pigmented, thin-walled cells of textura prismatica. Hamathecium comprising dense, long, pseudoparaphyses, septate, branching and anastomosing above asci, embedded in a gelatinous matrix. Asci 8-spored, bitunicate, fissitunicate, cylindrical to cylindro-clavate, with a furcate pedicel, apically rounded with an ocular chamber. Ascospores bi-seriate to partially overlapping uni-seriate, hyaline, then becoming pale brown at maturity, fusoid, ellipsoid or oblong with narrowly rounded ends, 1-septate, deeply constricted at the septum, the upper cell often broader than the lower one, wall smooth or verruculose. Asexual morph: Pyrenochaeta or Pyrenochaeta-like (Sivanesan 1984). Pycnidia solitary or gregarious, formed in culture from a single ascospore isolate (Bose 1961), superficial, with or without hairs, globose to pyriform or hemispherical, ostiolate. Ostiole single, papillate with a long or short neck. Peridium wall composed of textura angularis. Conidiogenous cells simple, cylindrical, branched, phialidic. Conidia hyaline, globose to ovoid or cylindrical, straight or curved, one-celled, with or without guttules (Adapted from Tian et al., 2015).
Type species: Herpotrichia rubi Fuckel
Notes: Herpotrichia was introduced by Fuckel (1868) to accommodate two species Herpotrichia rhenana and Herpotrichia rubi without designation of a type. Herpotrichia is characterized by scattered to gregarious, immersed ascomata, fissitunicate, cylindrical to cylindro-clavate asci and fusoid, ellipsoid or oblong 1-septate ascospores. The asexual morph is Pyrenochaeta or Pyrenochaeta-like characterized by solitary or gregarious pycnidia, papillate ostiole with a long or short neck, cylindrical, branched, phialidic conidiogenous cells and hyaline, globose to ovoid or cylindrical conidia (Tian et al., 2015). Bose (1961) chose H. rhenana as the lectotype species and this was followed by Müller and von Arx (1962) and Sivanesan (1971). Holm (1979) suggested H. rubi to be the generic type of Herpotrichia based on rules of nomenclature since it was formally published two years before H. rhenana (Cannon, 1982; Tian et al., 2015) but since Sphaeria herpotrichoides (= H. rubi) is the earliest name, the latter was chosen as the type of the genus. Herpotrichia resembles Melanomma in having immersed, erumpent to superficial ascomata, embedded on a subiculum, but differs in that ascospores in Herpotrichia are hyaline and 1-septate turning brown with more septa. Herpotrichia differs from Pseudotrichia in having large ascomata with compact apices while Herpotrichia has smaller ascomata on a subiculum (Bose, 1961; Barr, 1984). Herpotrichia also resembles Byssosphaeria but differs in lacking the reddish-orange or greenish tint near the ostiole which is present in Byssosphaeria. Zhang et al. (2012) suggested numerous criteria such as substrate, location and habitat to obtain a natural concept for Herpotrichia. Tian et al. (2015) added Herpotrichia vaginaspora to the genus and Herpotrichia was polyphyletic in their phylogenetic tree. Several authors added new species to Herpotrichia (Fröhlich & Hyde, 2000; Jones & Vrijmoed, 2003; Chen & Hsieh, 2004). Herpotrichia is morphologically and phylogenetically a distinct genus in Melanommataceae but sequences data for the type species H. herpotrichoides is needed to resolve the taxonomy of the genus.