Basidiome annual, sessile, occasionally stipitate, solitary, light in weight, consistency corky-woody; pileus projecting 4–8 cm, 6–14 cm wide, up to 1.5–1.8 cm thick at the base, 0.3–0.4 cm at the margin, dimidiate, flabelliform to conchate in pole view, applanate or slightly convex in section; stipe absent or 2 × 0.5–3 cm, horizontal, short and thick, slightly swollen at the base, laccate, smooth, reddish brown (8F6) to violet brown (11F7); pileal surface laccate, smooth, radially zonate, with dark lines or with concentric variably deep sulcations, reddish brown (8F6) to dark brown (8F5), lighter towards the margin; margin likely white when young, entire to slightly lobulated, sometimes incurved; pore surface yellowish white to greyish yellow (4C7), yellowish brown (5E7), or brownish orange (5C3), bruising dark brown (6F5), sometimes marked with spots of same aspect as pilear surface (laccate, reddish brown, 8F6); pores round, 4–6 (–7) per mm; context 0.2–1 cm thick, fibrous, homogeneous to slightly heterogeneous (not fully homogeneous fideTorres-Torres et al. 2012), almost overall white to light yellow (4A4) or light yellow (4A4) to greyish orange (5B4) toward the crust, yellowish brown (5D6) to light brown (7D3) in a narrow zone above the tubes, with few to several resinous incrustations or thin resinous dark bands stretching from the basis to the margin; tubes 0.1–0.8 cm long, unstratified, concolorous with lower part of the context.

Hyphal system dimitic; generative hyphae 1–3 µm diam., septate, thin-walled with clamp connections, little branched, hyaline to yellowish; somatic hyphae as arboriform skeleto-binding hyphae, golden yellow, composed of a basal stalk arising from a clamp, unbranched, thick-walled but with a visible lumen, with several secondary processes, branches gradually tapering from 6 µm wide in the primary processes to 1.5–2 µm wide at the thin-walled apices, thick-walled to solid. Pileipellis a crustohymeniderm; cuticular cells clamped at the basal septum, shortly to moderately pedicelated then cylindrical a clavate, occasionally slightly apically capitate, rarely with 1–2 lateral branches, with rounded apices, thick-walled, smooth or with a fine apical granulation, amyloid, 25- [~ 40] -50 (-65) × 5-7 um. Hymenium: basidia not seen; basidiospores ovoid to broadly ovoid, the apex shrunken, appearing truncate, exosporium with thick, free to subfree pillars, (7.5–) 8– [8.5] –9 (–10.5) × (4.2–) 6– [6.5] –7 (–8) µm, Q = 1.33– [1.30] –1.28; spore print light brown (6E5) (estimated from spore deposit on the pileus). Chlamydospores in the basidiomata absent, rare, to variably abundant, only in the context, subspherical, ellipsoid, or citriform, terminal or intercalated; with smooth thick-wall; sometimes guttulate, dextrinoid, 9.5–13 (–16) × 8–10 µm. Chlamydospores always abundant in pure culture on malt agar, spherical to more often ellipsoid, terminal or intercalary, when terminal with the apex occasionally papillated; with smooth, hyaline to pale golden brown, single or double wall; sometimes with densely guttulate contents, often dextrinoid, 11–16 × 9.5–12 µm.

MEXICO. Estado de México: D. de Jonacatepec, Tepalcingo, 22 Oct 1890, P.J.B. Maury 4823 (FH 458184!).

Argentina, Brazil, Martinique, Mexico.

ARGENTINA. Buenos Aires: Tigre, on Platanus sp., 15 May 1980, Connon (as holotype of G. subamboinense var. laevisporum, BAFC 25525, culture ex. type BAFC n° 247 = ATCC 52419). MARTINIQUE. Prêcheur: Anse Couleuvre, sentier de la cascade de la rivière Couleuvre, on Artocarpus altilis, in mature, secondary mesophylic forest, 13 Aug 2007, J.P. Fiard SW 17 (LIP, culture ex. MUCL 49453). Rivière–Pilote: Morne Aca, on a lying trunk, in meso-xerophylic forest, 14 Aug 2007, S. Welti, SW 19 (LIP). La Caravelle, xerophylic forest, on dead fallen trunk, 12 Aug 2015, C. Decock, MA/15–45 (MUCL 55832, culture ex. MUCL 55832). MEXICO. Morelos: Municipality of Cuernavaca, on dead wood, 24–27 December 1909, W.A. & E.L. Murrill 392 (as holotype of G. sessiliforme, NY 985713). Mpio. of Tepoztlán, Tepoztlán, Estación del Ferrocarril El Parque, w/o date, G. Guzmán 2078 (ENCB). Veracruz: San Andrés Tlalnelhuayocan, alrededores de San Antonio Hidalgo, bosque mesófilo de montaña, 1400 m, D. Jarvio 143 (XAL).