Mycena miscanthi T.Bau & Q.Na sp. nov. Figs 2i, 6

Diagnosis.

Growing on dead stem of Miscanthus . Pileus sparsely pruinose. Basidiospores cylindric. Cherocytes absent. Acanthocysts forming two types. Caulocystidia sphaero-pedunculate covered with spines. Clamps present.

Holotype.

CHINA. Henan Province: Xinyang City, Jigong Mountain, 16 Jul 2017, Qin Na and Tolgor Bau, HMJAU 43584.

Etymology.

Name refers to the substratum where the new species was found.

Description.

Pileus 3.5-7.8 mm in diam., hemispherical, broadly conical to convex, occasionally ± centrally depressed when young, sulcate, translucent-striate, pure white, pubescent to inconspicuously puberulous, margin nearly plane, undulate. Context white, thin, very fragile, about 1.0 mm thick at centre. Lamellae narrowly adnate or adnexed, off-white, concolorous with the sides. Stipe 26-38 × 0.5-1.0 mm, pure white, central, terete, hollow, equal, surface covered with slight white pubescent, base swollen but not discoid, pruinose. Odour and taste not distinctive.

Basidiospores (6.2-)6.7-8.6(-9.1) × (3.1)3.3-4.2(4.5) μm, Q=1.8-2.3, Qav=2.07, cylindric to narrow-ellipsoid, hyaline, guttulate, thin walled, amyloid. Basidia 18-24 × 6-9 μm, clavate, hyaline, 4-spored. Cheilocystidia 13-26 × 9-14 μm, abundant, lageniform, utriform or sphaero-pedunculate, with short and conical spines. Pleurocystidia absent. Pileipellis hyphae 3-8 μm wide, strongly dextrinoid; cherocytes absent; universal veil composed of acanthocysts, forming two types, pyriform, vesicular or clavate, 12-32 × 10-17 μm, inamyloid. Hyphae of the stipitipellis 2-8 μm wide, with coarse excrescences, 0.9-2.8 × 0.5-0.9 μm, strongly dextrinoid; caulocystidia abundant, elliptic, utriform, sphaero-pedunculate, 15-37 × 7-15 μm, with conical or cylindrical spines inamyloid. Clamps present in all tissues.

Habit and habitat.

Solitary to scattered on dead stem of Miscanthus .

Other specimens examined.

Henan Province, Xinyang City, Jinniu Mountain, 14 Jul 2017, HMJAU 43573; Xinyang City, Bolden National Forest Park, 17 July 2017, Qin Na and Tolgor Bau, HMJAU 43582.

Remarks.

The distinctive features of Mycena miscanthi include a white, granulose pileus, a pubescent stipe without forming a basal disc, narrow-ellipsoid spores, two types of acanthocysts and growth on dead stems of Miscanthus species. In combination, these features support the placement of M. miscanthi in sect. Amparoina stirps Alphitophora . Similar to M. miscanthi, M. alphitophora and M. depilata produce pure white basidiomata, cylindric spores and sphaero-pedunculate and spinulose cheilocystidia (Desjardin 1995; Aravindakshan and Manimohan 2015). However, the two types of acanthocysts and longer caulocystidia can be used to distinguish M. alphitophora and M. depilata from M. miscanthi (Desjardin 1995). Mycena hemitrichialis is closely allied to M. miscanthi, but differs in producing caulocystidia up to 400 μm in length that lack spinulae or with a few spinulae in the upper half (Singer 1989). Mycena distincta, which was originally described as M. alphitophora var. distincta, was elevated to species level by Manimohan and Leelavathy (1989). It differs from M. miscanthi in producing broadly ellipsoid spores and caulocystidia up to 300 μm in length (Aravindakshan and Manimohan 2015). The pigmented pileus present in M. brunneospinosa, M. incarnativelum and M. roseotincta readily distinguishes these species from M. miscanthi (Desjardin 1995; Aravindakshan and Manimohan 2015). Mycena corynephora, M. globispora and M. yalensis of stirps Alphitophora are characterised by globose to subglobose spores (Maas Geesteranus 1980; Robich 2003; Aravindakshan and Manimohan 2015; Aronsen and Læssøe 2016).