Mycena miscanthi T.Bau & Q.Na

Na, Qin & Bau, Tolgor, 2019, Recognition of Mycenasect. Amparoina sect. nov. (Mycenaceae, Agaricales), including four new species and revision of the limits of sect. Sacchariferae, MycoKeys 52, pp. 103-124 : 103

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).