Helicascus Kohlm., Can. J. Bot. 47: 1471 (1969).
Saprobic on wood. Sexual morph: Stromata with several locules, black, immersed in dead mangrove wood. Ascomata depressed ampulli-form, horizontally arranged under a black pseudocly-peus, united radially into valsoid groups; ostioles connected into a common, central, periphysate porus. Hamathecium of numerous, persistent, anastomosing,delicate threads. Asci eight-spored, subcylindrical to oblong clavate, stipitate, fissitunicate, thick-walled,with an apical apparatus. Ascospores oboboidal, one-septate, constricted at the septum, brown; walls two-layered, covered by a mucilaginous sheath. Asexual morph: Unknown (Adapted from Hyde et al., 1991).
Type species: Helicascus kanaloanus Kohlm.
Notes: Helicascus was introduced by Kohlmeyer (1969) with H. kanaloanus as type species. Helicascus is characterized by black stromata with several locules, depressed ampulli-form ascomata, subcylindrical to oblong clavate asci and subcylindrical to oblong clavate ascospores covered by a mucilaginous sheath. Hyde et al. (1999) added a new species Helicascus nypae from dead intertidal fronds of Nypa fruticans in Brunei. Zhang et al. (2013) added two more Helicascus taxa H. aegyptiacus and H. aquaticus from freshwater habitats and transferred two species of Massarina to Kirschsteiniothelia as H. thalassioideus and H. elaterascus. Zhang et al. (2014) described Helicascus gallicus from aquatic habitats in western and southern France. Several new species have been consequently added to Helicascus (Zeng et al., 2013; Zhang et al., 2015; Luo et al., 2016; Yang et al., 2016; Preedanon et al., 2017). Jones et al. (2009, 2015) and Zhang et al. (2012) showed that Helicascus is a monophyletic genus in Morosphaeriaceae. Helicascus is morphologically and phylogenetically a distinct genus in Morosphaeriaceae. Molecular data available for Helicascus include LSU, SSU, ITS, TEF1 and RPB2.