Gymnopus similis Antonín, R. Ryoo & K.H. Ka

Li, Ji-Peng, Li, Yu, Li, Tai-Hui, Antonín, Vladimír, Hosen, Md Iqbal, Song, Bin, Xie, Meng-Le & Feng, Zhan, 2021, A preliminary report of Gymnopus sect. Impudicae (Omphalotaceae) from China, Phytotaxa 497 (3), pp. 263-276 : 271

Gymnopus similis Antonín, R. Ryoo & K.H. Ka in Ryoo et al., Phytotaxa 268(2): 82, 2016. ( FIGURES 2e–g and 5 )

Description:—Basidiomata gregarious. Pileus 10–33 mm broad when dry, plano-convex to applanate, with plane or slightly depressed centre and inflexed then straight margin, surface shallowly sulcate-striate except for the smooth or rugulose centre, light brown (6D5), orange white (5A2) to greyish orange (6B3) when old. Lamellae emarginate, L = 16–21, l = 1–3, rugulose-intervenose at the base, orange white (5A2) to greyish orange (6B3). Stipe 55–95 × 1–4 mm, cylindrical to clavate, 1–2 mm thick at the centre, sometimes grooved, laterally compressed or equal to slightly inflated to nearly clavate towards the base ( 2–4 mm), densely whitish tomentose, orange white (6A2) to greyish orange (6B5) or reddish white (7A2) when old; with a whitish to light ochraceous basal tomentum. Odour distinct, like garlic.

Basidiospores 6–7.5 (‒10) × 2.5–3 (‒3.5) μm, (average = 6.8 × 3.0 μm, n = 40, E = 2.00–2.33 (‒2.67), Q = 2.24), ellipsoid, sublacrymoid, hyaline, thin-walled. Basidia indistinct (possibly because the sample has been overdried and is in non-ideal state), most likely with the similar size and shape to basidioles. Basidioles 14.5–32 × 3.5–6 μm, cylindrical to clavate. Cheilocystidia rare, 14‒39 × 3‒8 μm, clavate, subcylindrical to irregular, thin-walled. Pleurocystidia absent. Pileipellis a cutis composed of cylindrical, thin- to slightly thick-walled, smooth, up to 9 μm wide hyphae; terminal cells cylindrical, slightly coralloid at the apex, obtuse, smooth. Stipitipellis a cutis composed of cylindrical, parallelly arranged, slightly thick-walled, smooth, 4–8 μm wide hyphae. Caulocystidia numerous, 20–53 × 4.5–10 μm, cylindrical, narrowly clavate to sometimes irregular or branched, obtuse, hyaline, thin-walled. Clamp connections present.

Habitat: —Gregarious on debris in a broad-leaf forest.

Material studied: — CHINA, Zhejiang Province, Hangzhou City, West Lake , 30° 25’ 89” N, 120° 14’ 34” E, alt. 15 m, 8 September 2019, Z. Feng ( GDGM 78308 ) .

Remarks:— Gymnopus similis is characterized by a rather pale coloured pileus, distant lamellae ruguloseintervenose at the base, a distinct garlic smell, moderately large basidiospores and numerous, versiform cheilo- and caulocystidia ( Ryoo et al. 2016). The Chinese collection differs from the type collection by the lack of numerous cheilocystidia and slightly smaller basidiospores based on the comparison with the original description [The spore size of the type (BRNM 766739) was (6‒) 6.5–8 (‒9) × 2.7–4 μm ( Ryoo et al. 2016)]. However, the phylogenetic analyses suggested that they are conspecific. This collection represents the first record to China.

Figures

FIGURE 2. Basidiomata of Gymnopus species. a–b. Gymnopus alliifoetidissimus (GDGM 76695!, holotype), c–d. G. densilamellatus (c. HMJAU 49127, d. HMJAU 49128), e–g. G. similis (GDGM 78308). a–b: photographed by J.P. Li, c–d: photographed by M.L. Xie, e–g: photographed by Z. Feng.

FIGURE 5. Microscopic features of G. similis (GDGM 78308). a. Basidiospores, b. Basidioles, c. Cheilocystidia, d. Caulocystidia, e. Pileipellis terminal cells. Scale bars, a–c = 10 μm, d–e = 20 μm.