Lamellae free, moderately crowded, white when young, white to cream colored when mature, sometimes slightly with pinkish tinge, thin, with lamellulae. Stipe whitish,

subcylindrical, 9–11 × 1.0–2.0 cm, gradually attenuating upwards, glabrous or with shiny hairs, hollow; base slightly selleck chemical enlarged to subglobose, 3.5–4.0 cm wide. Annulus ascending, whitish, membranous, slightly complex, with brownish patchy squamules on the underside. Context white to whitish, spongy, unchanging color when cut, but at edge of stipe slightly with wine red tinge, odorless. Taste mild or indistinct. Basidiospores (Fig. 5c) [136/8/6] (12.0) 13.0–15.0 (16.0) × (7.5) 8.5–10.0 (10.5) μm, Q = (1.38) 1.40–1.63 (1.67), avQ = 1.50 ± 0.08, ellipsoid to ovoid in side view, ellipsoid in front view, thick-walled, smooth, hyaline, dextrinoid, congophilous, metachromatic in cresyl blue, with a germ pore caused by an selleck screening library interruption in the episporium on the rounded apex, covered with a hyalinous cap in KOH; apiculus not distinctive, about 1 μm long. Basidia (Fig. 5d) 35–52 × 13–16 μm, clavate, thin-walled, hyaline, 4-spored rarely 2-spored. Cheilocystidia (Fig. 5e) 20–43 × 9.5–15 μm, obtusely fusiform to subclavate

in most cases, occasionally subcylindric to vesiculose, hyaline, thin-walled, in bunches forming a sterile edge. Pleurocystidia absent. Squamules on pileus (Fig. 5b) a palisade of subcylindric, clampless hyphae (20–65 μm in length, 5–10 μm in diam.), seldomly branched, with terminal elements slightly attenuate toward the tip, with yellowish to brownish vacuolar pigment, slightly thick-walled. Clamp connections common at ubiquitin-Proteasome system the base of basidia and cheilocystidia. Habitat and known crotamiton distribution in China: Terrestrial and saprotrophic, solitary to scattered in open meadows or under bushes. Distributed in northern and southwestern China (Inner

Mongolia and Sichuan). Materials examined: Inner Mongolia Autonomous Region: Wulanchabu (Ulanqab) City, alt. 1590 m, 1 Aug. 1990, P. G. Liu 623 (HKAS 23040); Aug. 1994, X. L. Mao 8111 [HMAS 63157 (M); Aug. 1994, X. L. Mao 8116 [HMAS 73304 (M); Sichuan Province: Xiangcheng County, alt. 3000 m, 12 July 2004, Z. W. Ge 96 (HKAS 45863, holotype); Xiangcheng County, shagong, alt. 3000 m, 11 July 1998, Z. L. Yang 2286 (HKAS 32153); on the way from Jiulong County to Mianning County, 16 July 2005, Z. W. Ge 505 (HKAS 49001). Comments: Macrolepiota orientiexcoriata is characterized by the combination of brownish to reddish-brown furfuraceous squamules composed of a palisade of subcylindric, seldomly branched, clampless hyphae, and the obtusely fusiform to subclavate cheilocystidia. Macrolepiota orientiexcoriata is very close to M. excoriata (Schaeff.) Wasser both morphologically and molecularly. However, M. excoriata has a pileus with an indistinct umbo, the pileal squamules are more often star-shaped, and the stipe is smooth (Candusso and Lanzoni 1990; Breitenbach and Kränzlin 1995; Vellinga 2001).