Cystoderma japonicum Thoen & Hongo, Trans. Mycol. Soc. Japan 26(1): 23 (1985)

Index Fungorum number: IF 105232; MycoBank number: MB 105232; Facesoffungi number: FoF 17128; Figs. 1, 2

Pileus around 20 mm in diam. when young, plano-convex, convex, gradually flattening with age, with a distinct umbo central, surface dry, yellowish-ochre, orange-yellow covered fine granular warts, or with a fine powder, an incurved margin at first, then applanate to plane with age, the margin usually appendiculate with remnants of partial veil, yellowish-ochre and yellowish-white. Lamellae whitish, adnate to adnexed, subdistant, with 1–2 lamellulae of different lengths, ventricose. Stipe 26 × 40 mm, cylindrical, with evanescent floccose-scaly ring zone, above the ring zone scattered silky striate, whitish to yellowish, below the ring densely covered with furfuraceous squamules, yellowish to light orange. Odor and taste are undocumented.

Basidiospores (4.8–)5.1–5.9(–6.1) × (2.4–)2.6–3.1(–3.4) µm (x̄ = 5.5 ± 0.4 × 2.9 ± 0.2, Q = 1.7–2.1, Qm = 1.9 ± 0.2, n = 30), elongate-ellipsoid in side view and front view, smooth, thin-walled, hyaline, inamyloid. Basidia 15.6–20.4 × 5.4–7.0 µm, clavate, hyaline and thin-walled, with 4-spored. Cystidia absent. Pileipellis on the upper layers composed of chains of numerous sphaerocytes, globose to subglobose, ellipsoid, slightly thick-walled, the lower layers composed of tightly interwoven hyaline hyphae, branched. Ring zone composed of hyaline hyphae, with attached sphaerocytes. Clamp connections present.

Material examined – CHINA, Hubei Province, Shennongjia National Park, 31°27’N 110°16’W, ca. 2886 m asl, 26 Aug 2022, Mao-Qiang He and Mei-Qi Wang, ZRL20221003 (HMAS 287966).

GenBank – HMAS 287966: PQ620226 (ITS).

Notes – This species is characterized by yellow-ochre to orange-yellow pileus, a persistent membranous ring on stipe and inamyloid ellipsoid basidiospores (Saar et al. 2009). The morphological and molecular data from the Chinese specimen is consistent with the holotype (Fig. 1). New geographical record from the Shennongjia National Park, China.

Figure 1 – Maximum Likelihood tree of Cystoderma inferred from ITS and nrLSU sequences data, rooted with Crucibulum leave. Branches supported by both BS = 70% and PP = 0.90 were labeled. The examined specimens in this study are bolded.

Figure 2 – Cystoderma japonicum. a, b Basidiomata. c Basidiospore. d Basidia. Scale bars: a–b = 1 cm, c–d = 5 µm.