Mycena griseotincta 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 griseotincta T.Bau & Q.Na sp. nov. Figs 2 f–g, 4

Diagnosis.

Pileus, lamellae and stipe with greyish tint, especially when old. Stipe base swollen. Basidiospores pip-shaped. Pileipellis with two types of acanthocysts. Caulocystidia up to 200 μm long with spines.

Holotype.

CHINA. Yunnan Province, Diqing Tibetan Autonomous Prefecture, Shangri-La Pudacuo National Park, 14 August 2018, Qin Na, HMJAU 43800.

Etymology.

Name refers to the grey-tinted basidiomata.

Description.

Pileus 1.5-12.8 mm in diam., conical when young, campanulate with age, obtusely umbonate in the centre, translucent-striate, white, greyish-white when old (4B1), floccose, pubescent, pruinose, with crenate margin when young, then becoming nearly plane and finely torn. Context pure white, thin, fragile. Lamellae 0.2-0.5 mm thick, narrowly adnate or adnexed, pure white to slightly pale grey (4B1); edges finely torn, concolorous with the sides. Stipe 13-64 × 0.5-1.0 mm, central, terete, almost equal or slightly tapering to apex, hollow, greyish-white (5B1), pubescent or puberulous, with white, fine hairs, base swollen. Odourless, taste mild.

Basidiospores (5.6-)6.3-8.2(-8.5) × (3.5-)4.2-4.6(-5.2) μm, Q=1.5-1.9, Qav=1.7, pip-shaped, hyaline, guttulate, thin walled, amyloid. Basidia 19-23 × 7-9 μm, hyaline, clavate, 4-spored. Cheilocystidia 17-28 × 11-19 μm, oblong or clavate, with short and sharp spines, hyaline, inamyloid. Pleurocystidia absent. Pileipellis hyphae 6-10 μm wide, strongly dextrinoid; cherocytes absent; acanthocysts of two types, pyriform to vesicular, 8-22 × 7-18 μm or clavate to cylindric, 17-51 × 8-13 μm; universal veil composed of acanthocysts, globose, subglobose or sphaero-pedunculate, 28-67 × 26-58 μm, hyaline, covered with long, cylindrical excrescences or long and flexuous spinules, not in chains. Hyphae of the stipitipellis 2-7 μm wide, dextrinoid; caulocystidia abundant, clavate or long cylindrical, 77-216 × 9-11 μm, covered with densely conic spines, inamyloid. Clamps not seen.

Habit and habitat.

Scattered to gregarious on litter layer in Quercus , Picea , Abies , Pinus mixed forests.

Other specimens examined.

Yunnan Province, Diqing Tibetan Autonomous Prefecture, Shangri-La Pudacuo National Park, 15 August 2018, Qin Na, HMJAU 43805; Tibet Autonomous Region, Nyingchi City, Zhuqudeng Village, 20 August 2018, Qin Na, HMJAU 43819.

Remarks.

Mycena griseotincta is considered a new species in sect. Amparoina stirps Alphitophora on account of the absence of both a basal disc and cherocytes on the pileal surface ( Desjardin 1995). Five species have ellipsoid basidiospores, caulocystidia covered with excrescences and a universal veil composed of acanthocysts: M. alphitophora , M. brunneospinosa , M. depilata , M. hemitrichialis and M. incarnativelum . Mycena alphitophora most resembles M. griseotincta , but the former differs in having pure white lamellae, a white and shorter stipe (<50 mm), sphaero-pedunculate or obovoid cheilocystidia and larger spores (8.1-9.7 × 4.5-5.5 μm), as reported in the original description ( Maas Geesteranus 1980, 1992b). Mycena brunneospinosa , a taxon named by Desjardin (1995), is readily identified by its dull brown or purplish-brown pileus, globose acanthocysts forming chains and broadly ellipsoid spores. Mycena incarnativelum is a unique species in sect. Sacchariferae , distinguished by the absence of cheilocystidia and deep pink basidiomata when young ( Desjardin 1995). Mycena depilata is closely allied to M. griseotincta , but differs in the convex pileus less than 1 mm in diameter and short and broadly clavate caulocystidia ( Singer 1989). Mycena hemitrichialis can be mistaken for M. griseotincta on account of its grey or pallid pileus and ellipsoid spores, but is distinguished from M. griseotincta by its white stipe, free lamellae and pilose stipe forming a flattened ring of mycelium ( Desjardin 1995). Mycena corynephora is widely distributed worldwide and is recognised by its tiny basidiomata (pileus <2.4 mm), absence of a basal bulb or basal disc and large globose to subglobose basidiospores, typical of stirps Alphitophora ( Desjardin 1995; Robich 2003; Aronsen and Læssøe 2016). The same spore shape occurs in M. yalensis of which the holotype was collected from Argentina ( Singer 1973). Aravindakshan and Manimohan (2015) reported one new species and two others newly combined in Mycena , collected from India. The new taxon, M. roseotincta , differs from M. griseotincta in its pink pileus and universal veil, subcylindrical spores and smaller caulocystidia ( Aravindakshan and Manimohan 2015). Mycena globispora and M. distincta are mainly distinguished in macromorphology from M. griseotincta by their white basidiomata and, in micromorphology, by the globose spores and subcylindrical spores, respectively ( Aravindakshan and Manimohan 2015).