Agaricus pallidobrunneus

Pileus 105 mm in diam., 7 mm thick at disc, convex to plane; surface dry, whole cap covered by fibrils, and broken into small squamules, appressed or upturned, dense at the disc and brown, light brown towards the margin; margin decurved and exceeding. Lamellae free, 11 mm broad, ventricose, crowded, intercalated with lamellulae, reddish brown, brown with age. Stipe110 × 13– 20 mm, cylindrical and widening towards base, slightly clavate, hollow, surface white, smooth and white above the annulus, covered by small squamules which are the same as those of the pileus at the lower of annulus, not staining on touching. Annulus membranous, double, large, entire, with crenate edge, pendant, upper surface (upper layer) smooth, white and lower surface (lower layer) floccose, white and light brown towards the margin. Context firm, on cutting greyish white both in pileus and stipe, not discolouring on exposure. Odour pleasant. Macrochemical reactions: KOH reaction yellow, Schäffer’s reaction negative. Basidiospores 6.1–7.8 × 3.5–4.5 (−5.2) μm, [x = 6.7 ± 0.4 × 4.3 ± 0.4, Q = 1.4–1.8, Qm = 1.6 ± 0.1, n= 20], ellipsoid to oblong, brown, smooth, thick-walled, without germ pore. Basidia 16–3×6–9 μm, clavate to broadly clavate, hyaline, smooth, 4-(2-) spored. Cheilocystidia 17–35 × 11–21 μm, abundant, simple, pyriform or sometimes in short chains, globose to ellipsoid, 11–25 μm in diam., hyaline, smooth. Pleurocystidia absent. Pileipellis a cutis composed of hyphae 4–18 μm in diam., shortly ellipsoid or cylindrical, with brownish membranous pigments, smooth, distinctively constricted at the septa.

Index Fungorum number: IF 570225, Mycobank: MB 570225, Facesoffungi number: FoF01182

Etymology: the epithet “pallidobrunneus” refers to light (pallido) brown (brunneus) coloured pileus.

Holotype: China, Yunnan Prov., Yongde county, Daxueshan Xiang, Pintian Village, 17 July 2012, collected by R.L. Zhao ZRL2012358 (HMAS273999, holotype).

Habitat: solitary in the forest.

Specimens examined: CHINA, Yunnan Prov., Yongde county, Daxueshan Xiang, Pintian Village, 17 July 2012, collected by R.L. Zhao ZRL2012358 (HMAS273999, holotype).