Agaricus lanipedisimilis P. Callac & R.L. Zhao.
Index Fungorum number: IF570220, MycoBank: MB570220, Faces of Fungi: FoF01199
Pileus 70–90 mm in diam., 3–8 mm thick at disc, parabolic when young and convex; surface dry, completely covered by appressed fibrils and broken into squamulestowards the margin, reddish brown (oac639), margin straight. Lamellae free, 5–8 mm broad, intercalated with lamellulae, crowded, at first white, then pink, reddish brown, finally dark brown. Stipe 100–150 × 8–16 (apex) and 18–30 (base) mm, clavate or cylindrical with wide base or bulbous, hollow, white, surface smooth to slightly fibrillose above the annulus, erected or recurved below the annulus, staining light yellow on touching. Annulus membranous, simple, pendant, upper surfaces smooth and lower surface floccose, up to 20 mm broad, white. Context fleshy, on cutting at first white, both in pileus and stipe, then slowly (after around 5 min) turning slightly pink, both in centre of pileus and stipe. Odour of strong almonds. Macrochemical reactions: KOH reaction yellow, Schäffer’s reaction negative. Basidiospores 4.8–6 (−7)×3.6–4.5 μm, [x = 5.2 ± 0.3 × 4 ±0.2, Q=1.1–1.4, Qm= 1.3 ± 0.1, n = 20], broad ellipsoid, brown, smooth, thick-walled, without germ pore. Basidia 14–20 × 6–8.4 μm, clavate to broadly clavate, hyaline, smooth, 4-spored. Cheilocystidia absent. Pleurocystidia absent. Pileipellis a cutis composed of 3–7.6 μm diam., longcylindrical hyphae with brownish membranous pigments, smooth, not constricted at the septa, or occasionally slightly constricted at the terminal cell. (Fig. 1 a-c; Fig 2)
Etymology: the epithet “lanipedisimilis” refers to the similarity of this species to A. lanipes. From the union of lanipedis, the genitive of lanipes, and similis.
Holotype: CHINA, Yunnan Prov., Cangyuan county, Mengjiao, Nangunhe National Natural Reserve, 9 July 2012, collected by R.L. Zhao, ZRL2012193 (HMAS 273998, holotype).
Habitat: solitary in the forest.
Specimen examined: CHINA, Yunnan Prov., Cangyuan county, Mengjiao, Nangunhe National Natural Reserve, 9 July 2012, collected by R.L. Zhao, ZRL2012193 (HMAS 273998, holotype). China, Yunnan Prov., Cangyuan county, Mengdong, Nangunhe National Natural Reserve, 7 July 2012, collected by Philippe Callac, ZRL2012151 (HMAS253918).
Notes: This new species is characterized by reddish brown fibrillose pilei, floccose stipe from the lower side of annulus to the base, and broadly ellipsoid basidiospores. This species is mostly similar to A. lanipes, which also has these characters. However, A. lanipes has rhizomorphs, brown-coloured fibrillose squamules on the stipe and septate to catenulate cheilocystidia, which are different from the new species. The phylogenetic analysis also supports them as distinct species. Agaricus planipileus is phylogenetically closest to A. lanipedisimilis, but morphologically different, owing to the light brown pileus and absence of cheilocystidia.