Zhuliangomyces olivaceus (Zhu L. Yang, Y.Y. Cui & Q. Cai) Redhead, Index Fungorum 385: 1 (2019)
Etymology: olivaceum, from olivaceus = olivaceous, referring to the olivaceous pileus of this species.
Basidioma small. Pileus 3–5 cm in diam., convex to applanate, broadly umbonate at center, dark olivaceous (5E3–6) to olivaceous (3E5–8), slightly paler when mature, strongly gelatinized, margin often non-striate, often with gelatinized appurtenances, trama white (1A1), unchanging. Lamellae free to nearly free, white (1A1) to cream (1A2). Stipe 5–7 × 0.4–0.8 cm, subcylindric, attenuate upwards, white (1A1) to dirty white (2B1), lower half with olivaceous (3E5–8) to grayish (1D2–4) squamules, strongly viscid, context white (1A1), unchanging, stipe base clavate to nearly clavate. Annulus gelatinized and disappeared when mature. Odor indistinct.
Basidiospores [50/3/2] 3.5–5.0 × 2.5–3.5 μm, Q = (1.11–) 1.21–1.56 (–1.6), Qm = 1.38 ± 0.11, broadly ellipsoid to ellipsoid, inamyloid, colourless, hyaline, thin-walled, slightly verruculose, apiculus relatively large. Basidia 23–35 × 5–8 μm, clavate, 4-spored, sterigmata 3–5 μm long. Lamellar trama bilateral. Mediostratum 20–40 μm wide, composed of abundant ellipsoid to clavate inflated cells (35–120 × 15–30 μm), filamentous hyphae abundant, 3–7 μm wide, vascular hyphae rare. Lateral stratum composed of abundant fusiform, ellipsoid to clavate inflated cells (55–100 × 10–40 μm), filamentous hyphae abundant, 2–8 μm wide, diverging at an angle of 30°–45° to the mediostratum. Subhymenium 30–60 μm thick, with 2–4 layers of subglobose, ovoid to ellipsoid or irregular cells (7–30 × 7–30 μm). Pleurocystidia and cheilocystidia not present. Pileipellis 150–250 μm thick, an ixotrichodermium composed of vertically arranged, pale olivaceous, olivaceous to dark olivaceous, septate, filamentous hyphae with terminal cells cylindric to narrowly clavate, 20–60 × 3–9 μm. Stipe trama composed of longitudinally arranged, ellipsoid to long clavate terminal cells (60–425 × 20–50 μm), filamentous hyphae abundant, 3–13 μm in diam., vascular hyphae rare. Clamps present at all parts of basidioma.
Habitat: On soil in a forest with Rhododendron, basidioma occurring in summer.
Distribution: Known from southwestern China.
Index Fungorum number: IF555448
Figure 1. Fresh basidiomata of species in Myxoderma. e M. ochraceoluteum (HKAS 77301), f–h. M. olivaceum (TYPE, HKAS 101960). Scale bars e–h = 2 cm
Figure 2. Microscopic features of Zhuliangomyces olivaceus (TYPE, HKAS 101960). a. Hymenium and subhymenium, b. Basidiospores, c. Pileipellis, d. Stipe trama. Scale bars: a = 10 μm, b = 2 μm, c = 30 μm, d = 50 μm
Redhead SA. 2019. Nomenclatural novelties. Index Fungorum. 385:1-1
Cui YY, Cai Q, Tang LP, Liu JW, Yang ZL. 2018. The family Amanitaceae: molecular phylogeny, higher-rank taxonomy and the species in China. Fungal Diversity 91: 5–230.