Leucoagaricus subtropicus Y. Yang, X. Luo & Y.P. Xiao, sp. nov. Fig 3
MycoBank number: MB 559770; Index Fungorum number: IF 559770; Facesoffungi number: FoF 12619
Etymology: The designation “subtropicus” refers to the subtropical climate of the locations where the species was collected.
Holotype: HKAS 124380
Diagnosis: Leucoagaricus subtropicus is distinguished by the following: pale red to brownish-red fibrous scales arranged in subconcentric rings pileus with dark violet brown central disk and finely striate towards the margin; occasional dehiscence at the edge of the cap when mature, greyish red to blood-red when bruised or on handling; amygdaliform or somewhat fusiform basidiospores; and presence of polymorphic cheilocystidia, at cylindrical and slightly expanded the base stipe often with brownish-orange droplets, and in the upper part with calypso pink to light lilac and non-dislodging annulus.
Description: Basidiomata medium-sized (Fig. 2a-c). Pileus 55-80 mm diam., oval-campanulate when young, then convex to flat, with a broad, low umbo in the middle; surface with small pale red （10A3）to violet brown (12F8) fibrous scales arranged in subconcentric rings, small scales sometimes inconspicuous, becoming smooth, tapering towards the periphery, more dark pale red in the disc area, sparser violet brown (11F8) scales elsewhere, occasional dehiscence at the edge of the cap when mature; finely striate towards the margin. Context, 1 × 3 mm thick towards center, becoming greyish red(10B4) to blood-red (10C8) when bruised or on handling. Lamellae medium dense, unequal, free, intercalated by 0-1 lamellulae of variable length, subventricose, dirty white(12A1) to pale pink(12A2), turning brownish-black(12F3) when dry, averaging about 8 mm broad, with lamellulae in 2-3 tiers, with the edge pale pink(12A2). Stipe 85-100 × 7-10 mm, centrally attached, white(12A4) when young, then gradually turning brownish-red(12E6), cylindrical and slightly expanded at the base, up to 14-16 mm, hollow, often with brownish orange (6C8) droplets in the lower part. Annulus broad, membranaceous, attached to the upper part of the stalk, calypso pink (13A2), gradually becoming lighter from the inside out, with tiny light lilac (15A4) scales, not easy to fall off. Odour is not distinctive. Taste not recorded.
Basidiospores 7.2-9.1 × 4.3-6.5 µm, Q= 1.67–2.12, Qav = 1.89, oblong-ellipsoid, amygdaliform or somewhat fusiform, with a conspicuous hilar appendix, smooth, thin- to slightly thick-walled, with inconspicuous germ-pore, hyaline, dextrinoid, cyanophilous, metachromatic in cresyl blue (Fig. 2d). Basidia 21.2–30.4 × 8.3–12.6 µm, clavate, hyaline, thin-walled, 3-or 4-spored; sterigmata up to 5 µm long (Fig. 2g). Lamella-edge crowded with tufts of cheilocystidia. Cheilocystidia abundant, 23.2–54.4 × 8.0–15.6 µm, mostly broadly pedicellate-clavate, at times narrowly utriform, or pedicellate-clavate, or narrowly rod-shaped to fusiform, or clavate with a mucronate apex or with a strangulated or flexuose, scattered at marginal (Fig. 2e). Pileipellis a trichoderm composed of tufts of ascending or erect chains of cystidioid elements (Fig. 2f); hyphae 6–15 µm wide, thin- to slightly thick-walled; terminal elements cystidioid 30–78 × 5–18 µm, narrowly clavate, clavate, subglobose, fusiform, cylindrical with an obtuse apex, ellipsoidal or utriform, thick-walled. Clamp connections not observed on any hypha mostly broadly.
Habitat and habit: scattered in the forest, in summer.
Material examined: CHINA. Anhui Province: Chuzhou District at 178m, 118.14 E, 32.25 N scattered or in small groups on loamy soil, 29 June 2021, HKAS 124380 (holotype); 29 June 2021, HKAS 1243801
Fig. 3 a,b,c Basidiomata, d Basidiospores, e Cheilocystidia f Pileipellis, g Basidia. Scale bars: a,b,c = 3 cm, c = 1 cm, d,g = 10 µm, e= 20 µm, f = 50 µm