Placosoma Syd., Annls mycol. 22(3/6): 302 (1924).
MycoBank number: MB 4139; Index Fungorum number: IF 4139; Facesoffungi number: FoF 08118; 2 morphological species (Species Fungorum 2020), molecular data unavailable.
Type species: Placosoma nothopanacis Syd., Annls mycol. 22(3/6): 303 (1924).
Notes: Placosoma was introduced by Sydow (1924) with a single species. Prasad et al. (1961) described a second species P. salvadorae. Thus, two species are accepted in this genus. Placosoma was placed in Asterinaceae by Lumbsch and Huhndorf (2010). However, Hongsanan et al. (2014b) re-examined the type species P. nothopanacis and suggested that Placosoma is typical of Parmulariaceae. Placosoma is characterized by superficial, circular, flattened, blackened, carbonaceous ascostromata, subglobose to oblong asci and broadly ellipsoidal ascospores with one septum (Hongsanan et al. 2014b).