Entonaema Möller is a distinctive xylariaceous genus known to have a tropical distribution, characterized by massive pulvinate, lobed to globose stromata, the interior being hollow, partially gelatinous, filled with liquid, in which the perithecia are developing in a single layer beneath a thin coloured outer crust. Asci and ascospores are typically xylariaceous, the former cylindrical, with an amyloid apical ring, the latter brown, ellipsoid, with a germ slit. (Rogers, 1981).

Although Möller (1901) already recognized the affinities of Entonaema with Xylariaceae and its position as a separate genus, the most unusual external habit of Entonaema species led to confusions with other xylariaceous genera (i. e., Xylaria, Penzigia, Sarcoxylon, Engleromyces) or with members of Hypocreaceae. Rogers (1981) did a comprehensive survey of the story of Entonaema and its putative affinities, and one year later, confirmed Entonaema as a xylariaceous genus in obtaining a Nodulisporium-like anamorph from E. liquescens (Rogers, 1982).

Recent chemotaxonomic (Stadler et al., 2004a) and molecular (Triebel et al., 2005) studies in various xylariaceous genera shed some light on affinities of Entonaema. The studied members of this genus appear closely related to Hypoxylon and Daldinia, some of them sharing with Hypoxylon certain specific compounds (mitorubrins) but yielding in culture same metabolites (naphtalene derivative and chromone) as Daldinia. However, at least two Entonaema species (E. mollucanum and E. pallida) are deviating in lacking mitorubrin but produce specific still unknown metabolites. Although these preliminary studies are promising, Entonaema remains a poorly known genus, owing to the scarce records of fresh material (Stadler et al., 2004a).

Until the records from southern Bulgaria (Benkert, 1993; Læssøe, 1997) and the present record from southwestern France, Entonaema was considered a genus with a tropical distribution (Rogers, 1981). A collection from Estonia is reported as very dubious by Rogers (1981).