Pileus densely pubescent to furfuraceous. Stipe arising from a well-developed basal disc or base swollen without a basal disc. Cheilocystidia with spines. Cherocystes present or absent. Acanthocysts present and overlying universal veil. Caulocystidia densely spinulose overall, never smooth.

Mycena spinosissima (Singer) Desjardin

Name refers to the name of stirps Amparoina.

Pileus furfuraceous to pruinose. Stipe without basal disc. Basidiospores small, 6.1–7.9 × 3.7–4.6 μm. Cheilocystidia clustered, sphaero-pedunculate to utriform with numerous sharp excrescences. Cherocytes absent. Acanthocysts pyriform to vesicular. Caulocystidia of two types, sphaero-pedunculate or clavate covered with conic spines. Clamps present.

CHINA. Chongqing City, Dafengbao Scenic Regions, 15 Aug 2017, Qin Na, HMJAU 43648.

Name refers to its two types of caulocystidia.

Pileus 2.8–5.2 mm in diam., conical when young, becoming nearly hemispherical with age, pure white all over, sulcate, translucent-striate, pruinose, furfur-like scattered, margin entire first, then nearly plane and finally fissile. Context very thin and fragile, pure white. Lamellae 0.5 mm thick, narrowly adnate, off-white, concolorous with the sides. Stipe slender, 15–28 × 0.5–1.0 mm, cylindrical, hollow, fragile, pure white, densely pruinose on the whole surface, base swollen and not forming a basal disc, hirsute. Odour and taste inconspicuous.

Basidiospores (5.6-)6.1–7.9(-8.3) × (3.5)3.7–4.6(4.9) μm, Q=1.6–2.0, ellipsoid to oblong-ellipsoid, hyaline, with drops, thin walled, amyloid. Basidia 20–26 × 6–9 μm, clavate, hyaline, 4- or 2-spored. Cheilocystidia 19–32 × 12–18 μm, clustered, sphaero-pedunculate to utriform with numerous sharp spines, thin-walled and hyaline, inamyloid. Pleurocystidia absent. Pileipellis hyphae 4–7 μm wide, weakly dextrinoid; cherocytes absent; a cutis overlaid by elements of universal veil, not in chains; acanthocysts of one type, numerous, pyriform to vesicular, 29–62 × 24–51 μm, inamyloid. Hyphae of the stipitipellis 3–14 μm wide, smooth, dextrinoid; caulocystidia abundant, of two types, utriform, sphaero-pedunculate, 21–85 × 14–66 μm or clavate, long-elliptic, 21–85 × 11–26 μm, densely and evenly spinulose overall, hyaline, thin-walled, inamyloid. Clamps present in all tissues.

Solitary to scattered on rotten wood in mixed forests, Bamboos, Cunninghamia, Ginkgo and Platycladus forests.

CHINA. Hubei Province, Enshi Tujia and Miao Autonomous Prefecture, Lichuan County, Yandongwan, 19 Jul 2017, Qin Na, HMJAU 43589; Xingdou Mountain National Nature Reserves, 20 Jul 2017, Qin Na, HMJAU 43593; Zhejiang Province, Hangzhou City, Tianmu Mountain National Nature Reserves, 4 Jul 2018, Qin Na and Tolgor Bau, HMJAU 43774.

Mycena bicystidiata is unique in sect. Amparoina stirps Alphitophora because of the two types of caulocystidia covered with conic spines. Mycena alphitophora, which is the most widely distributed species of sect. Amparoina, shows the most morphological similarities to M. bicystidiatum; however, the former differs in forming cylindric spores (7.5–10 × 4.5–5.5 μm), sphaero-pedunculate cheilocystidia and caulocystidia that are only clavate in shape (Desjardin 1995). Mycena depilata Singer is easily mistaken for M. bicystidiata by the stipe without a basal disc and the similar shape and size of spores and cheilocystidia, but M. depilata is distinguished from M. bicystidiata by its small basidiomata (pileus < 0.3 mm), larger spores (8.5–10 × 4.5–5.2 μm), and long-cylindrical and larger caulocystidia (30–120 × 5–20 μm) (Desjardin 1995). In contrast to M. bicystidiata, basidiospores of M. corynephora, M. distincta (Manim. & Leelav.) Aravind. & Manim., M. globispora (Manim. & Leelav.) Aravind. & Manim. and M. yalensis Singer are globose or broadly ellipsoid (Desjardin 1995; Aravindakshan and Manimohan 2015). The bright or dark colour on the pileus distinguishes M. brunneospinosa Desjardin, M. incarnativelum Desjardin and M. roseotincta Aravind. & Manim. from M. bicystidiata (Desjardin 1995; Aravindakshan and Manimohan 2015). In addition, M. hemitrichialis Singer produces caulocystidia that are only partially spinulose (Singer 1989).

Figure 2. 

Basidiomata of sect. Amparoina species. stirps Alphitophora: a–b Mycena alphitophora (Berk.) Sacc. c–d Mycena bicystidiata T.Bau & Q.Na e Mycena corynephora Maas Geest. f–g Mycena griseotincta T.Bau & Q.Na h Mycena hygroporoides T.Bau & Q.Na i Mycena miscanthi T.Bau & Q.Na; stirps Amparoina: j Mycena castaneicola T.Bau & Q.Na k–m Mycena heteracantha (Singer) Desjardin. Basidiomata of sect. Saccariferae species n–o Mycena hyalinostipitata T.Bau & Q.Na p–q Mycena substylobates T.Bau & Q.Na r Mycena tenerrima (Berk.) Quél. (=Mycena adscendens Maas Geest.) Scale bars: 10 mm (a–g, i–m, r), 5 mm (h, n–q). Photographs a–r by Qin Na.

Figure 3. 

Microscopic features of Mycena bicystidiata (HMJAU 43648, holotype) a Basidiomata b Basidiospores c Basidia d Universal veil acanthocysts e Cheilocystidia f Caulocystidia g Pileipellis. Scale bars: 5 mm (a); 10 μm (b–g). Drawing by Qin Na.

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.

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

Name refers to the grey-tinted basidiomata.

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.

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

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.

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).

Figure 4. 

Microscopic features of Mycena griseotincta (HMJAU 43800, holotype). a Basidiomata b Basidia c Basidiospores d Cheilocystidia e Universal veil acanthocysts f Pileipellis g Caulocystidia. Scale bars: 10 mm (a); 10 μm (b–g). Drawing by Qin Na.

Pileus concave with slight pruinose. Lamellae distant. Stipe with dense white fibrils and swollen base. Acanthocysts forming two types. Caulocystidia long-elliptic with conical excrescences, up to 120 μm long.

CHINA. Guangdong Province, Shaoguan City, Chebaling National Nature Reserve, 8 May 2017, Qin Na, HMJAU 43417.

Name refers to its sparse lamellae.

Pileus 1.5–2.5 mm in diam., campanulate to hemispherical, applanate or slightly concave at centre, white with greyish shade (6B1), shallowly sulcate, translucent-striate, slightly pruinose, pubescent. Context white, thin and very fragile. Lamellae distant, sparse, white, concolorous with the sides. Stipe 4.5–8.2 × 0.5–0.8 mm, cylindrical, hollow, fragile, pure white (5A1) with a greyish (5B1) base, covered with dense white fibrils, base swollen and not forming basal disc, hirsute. Odour and taste indistinctive.

Basidiospores (6.9-)7.2-8.9(-9.3) × (5.3-)6.4-6.7(-7.1) μm, Q=1.2–1.5, Qav=1.31, broadly-ellipsoid, hyaline in water and 5% KOH, amyloid, smooth. Basidia 15–21 × 7–9 μm, 4- or 2-spored, clavate, hyaline. Cheilocystidia 23–37 × 19–28 μm, subglobose, sphaero-pedunculate to utriform with numerous sharp spines, thin-walled and hyaline, inamyloid. Pleurocystidia absent. Pileipellis hyphae 3–9 μm wide, dextrinoid; cherocytes absent; a cutis overlaid by elements of universal veil, not in chains; acanthocysts forming two types, pyriform to vesicular, 13–29 × 11–24 μm, clavate to ovoid or obovoid, 29–42 × 14–20 μm, inamyloid. Hyphae of the stipitipellis 3–7 μm wide, smooth, dextrinoid; caulocystidia abundant, clavate, long-elliptic, 32–122 × 8–11 μm, with numbers of conical spines, inamyloid. Clamps present in all tissues.

Scattered on rotten wood of coniferous trees, ex. Cunninghamia.

Guangdong Province, Shaoguan City, Liangjiang Town, Shangxie Village, 7 May 2017, Qin Na, HMJAU 43421.

Mycena hygrophoroides could be considered to be a member of Hemimycena Singer owing to the tiny basidiomata and sparse lamellae, but the absence of a basal disc, amyloid spores and spinulose cheilocystidia, acanthocysts and caulocystidia are diagnostic characters for M. hygrophoroides, which should be placed in Mycena sect. Amparoina stirps Alphitophora. Mycena acanthophila J.C.Zamora&Català, of which the holotype was collected from Spain growing on dead branches of Leguminosae, most resembles M. hygrophoroides, but differs in having a yellow pileus, smaller cheilocystidia (13.5–22 × 8.5–12 μm) and diverse caulocystidia (Zamora and Català 2012). Mycena depilata, a species of stirps Alphitophora, shows some morphological similarities to M. hygrophoroides in possessing white and tiny basidiomata, distant lamellae (L = 7–9) and globose-pedicellate acanthocysts with hyaline contents. However, M. depilata differs in producing ellipsoid spores (Q = 1.64 ± 0.11), broadly clavate cheilocystidia and shorter caulocystidia (16–50 × 5–16 μm; Singer 1989). Mycena hemitrichialis is difficult to distinguish from M. hygrophoroides, but M. hemitrichialis has free to subfree lamellae, longer caulocystidia (100–300 × 5–15 μm) and ellipsoid spores (Singer 1989). In comparison with M. hygrophoroides, M. alphitophora and M. distincta have larger basidiomata and longer caulocystidia of more than 400 μm and 300 μm, respectively (Desjardin 1995; Aravindakshan and Manimohan 2015). Their noticeably pigmented pileus enables discrimination of M. brunneospinosa, M. incarnativelum and M. roseotincta from M. hygrophoroides (Desjardin 1995; Aravindakshan and Manimohan 2015). The significantly larger basidiomata and globose spores can be used to distinguish M. corynephora, M. globispora and M. yalensis from M. hygrophoroides.

Figure 5. 

Microscopic features of Mycena hygrophoroides (HMJAU 43417, holotype) a Basidiomata b Basidia c Basidiospores d Cheilocystidia e Universal veil acanthocysts f Caulocystidia g Pileipellis. Scale bars: 2 mm (a); 10 μm (b–g). Drawing by Qin Na.

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.

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

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

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.

Solitary to scattered on dead stem of Miscanthus.

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.

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).

Figure 6. 

Microscopic features of Mycena miscanthi (HMJAU 43584, holotype) a Basidiomata b Basidiospores c Basidia d Universal veil acanthocysts e Cheilocystidia f Pileipellis g Caulocystidia. Scale bars: 10 mm (a); 10 μm (b–g). Drawing by Qin Na.