Cibaomyces glutinis Zhu L. Yang, Y.J. Hao & J. Qin, in Yang et al., Phytotaxa 162(4): 203 (2014)
Etymology: glutinis refers to the glutinous pileus and stipe.
Basidiomata small to medium-sized. Pileus 3–4.5 cm, convex to applanate, strongly glutinous, dirty white to brownish to grayish (5B2–5B3, 5C2–5C3), finely rugose, often with brownish irregularly-shaped dots; center slightly darker. Lamellae adnate to sinuate or slightly decurrent, subdistant, with lamellulae, L = 20–25, l = 1–3, thick, dirty white to cream, sometimes with reddish to brownish spots, transversely veined, with lamellae frequently anastomosing; lamellar edge rusty brown to brownish. Context 2–3 mm thick, dirty white to brownish, unchanging in color when cut. Stipe 6–9.5 × 0.3–0.8 cm, subcylindrical, enlarged at ground line, surface dirt white to grayish, sticky, densely covered with brownish felted squamules but nearly white at apex; pseudorhiza dirty white. Taste mild; odor indistinct.
Spores [55/2/2] (9) 10.5–14 (15) × (8.5) 9–11.5 (12.5) μm, Q = (1.0) 1.05–1.24 (1.30), Qm = 1.14 ± 0.07, subglobose to broadly ellipsoid, thin-walled, colorless and hyaline, sometimes with brownish to brown contents, non-amyloid, non-dextrinoid, cyanophilous, non-metachromatic, with ca. 25 spines conspicuous, 2–4(5) μm high and 1.5–2 μm broad at base, hollow, conical to subcylindrical spines with obtuse apex. Basidia 50–70 × 13–15 μm, 4-spored, thin-walled, colorless hyaline, sometimes with yellowish brown contents; sterigmata up to 10 μm in length; basidioles clavate to subfusiform with subacute apex. Lamellar trama ± regular, composed of branching, nearly colorless and hyaline, slightly thick-walled (≤ 1 μm thick), filamentous to inflated hyphae 3–20 μm wide. Subhymenium composed of 3–5 μm wide frequently branching hyphal segments. Lamellar edge sterile, composed of crowded cheilocystidia; cheilocystida 50–130 × 4–8 μm, numerous, narrowly clavate, subcylindrical to cylindrical, often with a round to subcapitate apex, with brownish, brown to chocolate brown intracellular pigment, often incrusted brown substances. Pleurocystidia absent. Pileipellis an ixohymeniderm 40–60 μm thick, composed of clavate, broadly clavate to sphaeropedunculate, brownish to brown intracellularly pigmented cells (20–50 × 10–30 μm) embedded in a gelatinized matrix with brown to dark brown crystalline material. Pileocystidia abundant, subcylindrical to narrowly clavate, occasionally narrowly fusiform to lageniform, 40–80 × 4–8 μm, thin-walled, nearly colorless or with brownish to brown intracellularpigment, with apical parts often incrusted with brown, yellow-brown to ochraceous substances which are slowly soluble in KOH; apex narrowly rounded, rarely acute. Stipitipellis composed of vertically arranged, branching, nearly colorless and hyaline, slightly thick-walled (ca. 0.5 μm thick), filamentous hyphae 3–15 μm broad. Caulocystidia 50–100 × 3–8 μm, numerous and crowded, evenly distributed, narrowly clavate to subcylindrical, thin- to slightly thick-walled (ca. 0.5 μm thick), often with a round apex, with dark brown to yellow-brown intracellular pigment, occasionally nearly colorless and hyaline, often incrusted with brown to yellow-brown substances. Chlamydospores not observed. Clamp connections abundant in every part of basidioma.
Habitat and known distribution: fruiting in broad-leaved forests dominated by Fagaceae, on buried rotten wood; in summer at elev. 1000–2200 m in south-western China and northern Japan.
Index Fungorum number: IF807467
Figure 1. Phylogenetic tree generated from combined ITS and nrLSU dataset using ML method. Bootstrap values (≥ 50%) derived from ML analyses and posterior probabilities from Bayesian inference (≥ 0.95) are shown above or beneath the branches at nodes. Cibaomyces is highlighted in boldface.
Figure 2. Basidoma of Cibaomyces glutinis in its natural habitat. a. showing the pileus and the stipe. b. showing the lamellae and the stipe with a pseudorhiza (all from the holotype).