Pusillomyces J.S. Oliveira, in Oliveira et al., Mycological Progress. 18(5): 718 (2019)
Etymology: Pusillus (latin) = small; myces = mushroom; it refers to the small size of the marasmioid basidiomata.
Basidiomata marasmioid, thin, tiny. Pileus hemispheric to convex, or plane, sometimes slightly concave, center plane to depressed, with or without papilla, smooth, or slightly rugulose at the center, and striate-sulcate at the disc and margin, surface finely tomentose, membranous to firmly coriaceous. Hymenophore entirely smooth or with well-developed lamellae, adnate to occasionally adpressed to a false collarium, distant, whitish to pale cream. Stipe filiform, wiry, insititious, rising di-rectly from the substrate or branching from rhizomorphs; chitin-ous, horny, pliant, hollow; strongly pigmented, mostly brown to dark brown; glabrous or rarely finely pruinose, or even entirely pubescent to hairy. Rhizomorphs present, glabrous to pubescent, rare to abundant. Odor and taste not distinctive. Basidospores obovoid to shortly oblong, ellipsoid, ellipsoid-fusoid, lacrymoid to subclavate, smooth, hyaline, thin-walled, inamyloid. Basidia clavate, 2- to 4-sterigmate. Cheilocystidia not applicable (smooth hymenophore) or when present, in the form of Siccus-type broom cells. Pleurocystidia absent. Lamellar and pileus trama irregular, inamyloid, hyphae smooth or incrusted. Pileipellis non-gelatinized, non-hymeniform, a trichoderm of disorganized, packed elements, composed of cylindrical, thin- to slightly thick-walled, diverticulate, smooth or incrusted hyphae, mixed with elements similar to Siccus-type broom cells, or Rameales-structures. Stipitipellis and Stipe trama dextrinoid. Caulocystidia absent or present, dextrinoid. Clamp connections absent. In Melzer’s reagent, only the stipe trama is dextrinoid; otherwise, inamyloid. No staining in al-kaline solution (NH4OH or KOH).
Index Fungorum number: IF827357
Type species: Pusillomyces manuripioides J.S. Oliveira, in Oliveira et al., Mycological Progress. 18(5): 718 (2019)
Ecology: Saprotrophic or parasitic in plant (phytopathogen), epiphytic or in the forest litter, gregarious, on leafy or woody substrate.
Distribution: Probably worldwide; to date only recorded from the Neotropic (Tropical, Amazon forest, Brazil) and Paleoarctic regions (Temperate Broadleaf and Mixed Forest, Republic of Korea).
Pusillomyces asetosus (Antonín, Ryoo & Ka) J.S. Oliveira 2019
Pusillomyces funalis (Har. Takah.) J.S. Oliveira 2019
Pusillomyces manuripioides J.S. Oliveira 2019
Oliveira, JJS; Vargas-Isla, R; Cabral, TS; Rodrigues, DP; Ishikawa, NK. 2019. Progress on the phylogeny of the Omphalotaceae: Gymnopus s. str., Marasmiellus s. str., Paragymnopus gen. nov. and Pusillomyces gen. nov. Mycological Progress. 18(5):713-739