Life habit: saprobic or parasitic, not lichenized Thallus: vegetative parts of thallus unapparent or inconspicuous, immersed in the substrate Ascomata: apothecia, usually distinctly stalked, black to brownish black stalk: consisting of periclinally arranged to slightly irregular, narrow hyphae, dark brown to blue-green; in the central part sometimes with slightly swollen and paler hyphae capitulum: obovoid to lens-shaped; thalline exciple absent; true exciple: ±well developed, composed of dark brown, periclinally arranged hyphae with angular pseudoparenchymatous cells 5-15 µm in diam., or of anticlinally arranged, radiating and branched hyphae with swollen walls; mazaedium: absent, although a thin layer of mature spores is sometimes found on the surface of the apothecia hymenium: dark brown above; paraphyses: simple to sparsely branched asci: cylindrical, 35-65 µm long, formed singly from ascogenous hyphae with croziers, with strongly, uniformly thickened apex, or with a short and blunt canal penetrating the apex; with a single functional wall layer, persisting until maturity of ascospores ascospores: dark brown, simple, usually broadly fusiform, sometimes flattened, 5-11 x 3-5 µm, uniseriate, not released; wall: rather thick, well pigmented, smooth or with a minute verrucose ornamentation, without cracks Conidiomata: anamorphs coelomycetous; pycnidia rather common, black, spherical to ovoid or pyriform, ostiolate, occurring singly; wall: in the lateral part 5-10 µm thick, brown; in the outermost part consisting of tangentially arranged hyphae with gelatinous walls and small lumina: in the uppermost part distinctly thickened, 20-25 µm wide and consists of interwoven hyphae with a ±swollen basal part, brown in the apical part and with collarettes; conidiophores: type I of Vobis (1980) conidia: pale brown, rendering the conidium exudate a dark brown color, 4-5 x 1.5-2 µm, ±curved Secondary metabolites: in some species apothecia with tetronic acid derivatives (vulpinic and pinastric acids) Geography: cosmopolitan, cool to tropical in both the Northern and Southern Hemisphere Substrate: primarily saprobes on dry wood, more rarely on bark or as parasites on lichens. Notes: Some members of this genus are easily confused with Chaenothecopsis species, which differ in that the ascus apex is penetrated by a narrow canal. See Tibell (1998) for fuller description. According to phylogenetic analyses of nuclear rDNA ITS and LSU sequences Mycocalicium is not monophyletic (Tibell and Vinuesa 2005). Mycocalicium is, based on analyses of the nuclear rDNA SSU, considered part of the order Mycocaliciales (Tibell and Wedin 2000). Under the Conidiomata description above, the term "collarettes" refers to a frill or collar (often cup-shaped) of outer wall material remaining at the apex of a phialidic conidiogenous cell, following dehiscence of the first conidium.