Melaspilea Nyl., Act. Soc. linn. Bordeaux 21(4): 416 (1857) .
= Eremithallus Lücking, Lumbsch & L. Umaña, in Lücking et al., Symbiosis 46(3): 163 (2008). Type species: Eremithallus costaricensis Lücking, Lizano & Chaves, in Lücking, Lumbsch, Di Stéfano, Lizano, Carranza, Bernecker, Chaves & Umaña, Symbiosis 46(3): 163 (2008)
Index Fungorum number: IF 3094; Facesoffungi number: FoF 07676, 37 morphological species (Species Fungorum 2021), 3 species with molecular data.
Lichenized. Thallus thin, white, corticolous, with Trentepohlia photobiont. Sexual morph: Ascomata apothecioid, immersed when young, erumpent to superficial when mature, with a fat to slightly convex disk and a slightly elevated margin, often surrounded by marginal lobes from the substrate, roundish. Peridium reddish brown, K+ olivaceous brown at exciple issue, with a I- hymenium, apically not enlarged, cellular pseudoparaphyses that are sometimes branched or anastomosed, anastomosed periphyses arising from the inner excipular layer. Asci 6–8-spored, elongate or clavate to subcylindrical, wall apically thickened, with a distinct ocular chamber, I- and K/I-. Ascospores overlapping, 2-seriate, ellipsoid to oblong, hyaline to brown, 1-septate, constricted near the septum, smooth-walled, sometimes K/ I+ blue gelatinous sheath. Asexual morph: Undetermined (Adapted from Hongsanan et al. 2020).
Type species: Melaspilea arthonioides (A. Massal.) Nyl.
Notes: Melaspilea was introduced by Nylander (1857) with M. arthonioides as type species. Melaspilea traditionally accommodated species with crustose lichens with lirelliform apothecia and brown, 1-septate ascospores. Melaspilea sensu stricto resembles Eremithallus in ascomata, exciple, hamathecium, ascus and ascospores characters. Melaspilea also has similar ecology as Eremithallus mainly being lichenized with a trentepohlioid photobiont (Ertz and Diederich 2015). Ertz and Diederich (2015) reduced Eremithallus as a synonym of Melaspilea. This was followed by Wijayawardene et al. (2017a) and Hongsanan et al. (2020). Melaspilea as currently recognized is very heterogeneous and in need of a thorough revision.