Agaricus litoraloides

Agaricus litoraloides R.L. Zhao.

Index Fungorum number: IF570228, MycoBank: MB570228, Faces of Fungi: FoF01197

Pileus 30–80 mm in diam., 7 mm thick at disc, parabolic when young then convex; surface dry, covered by fibrils onthe whole cap, and broken into large squamules (3–5 mm wide), triangular, appressed, dark brown (oac637), reddish brown (oac635); margin exceeding. Lamellae free, 3–5 mm broad, crowded, reddish brown, brown, dark brown with age. Stipe 80–120× 11–20 mm, cylindrical to slightly clavate; stuffed or hollow; white; surface smooth above the annulus, and erect squamules below the annulus, staining light yellow on touching. Annulus membranous, simple, fragile, pendant, both surfaces smooth and white. Context fleshy, on cutting at first white, both in pileus and stipe, stipe quickly turning slightly rubescent on exposure. Odour strong of almonds. Macrochemical reactions: KOH reaction unknown, Schäffer’s reaction negative. Basidiospores 6.7–9 × 4.7-6.1 μm, [x = 8.2 ± 0.5 × 5.4± 0.3, Q= 1.3–1.8,Qm= 1.5 ± 0.1, n = 20], ellipsoid, occasionally oblong ellipsoid, brown to dark brown, smooth, thick-walled, without germ pore. Basidia 21–31×9.2–11.8 μm, clavate to broadly clavate, hyaline, smooth, 4-spored. Cheilocystidia 12.7–24.3 × 7.8–16 μm, abundant, simple, mostly broadly clavate, pyriform, hyaline, smooth. Pleurocystidia absent. Pileipellis a cutis composed of hyphae 2.5–12.3 μm in diam., cylindrical, with brownish membranous pigments, smooth, not or slightly constricted at the septa. Annulus composed of hyphae 2–10 μm in diam., cylindrical, hyaline, smooth. (Fig. 1 e-f; Fig 2)

Etymology: the epithet “litoraloides” refers to the morphological similarity of this new species to A. litoralis.

Holotype: CHINA, Yunnan Prov., Dali City, Cangshan, 30 July 2011, collected by H.Y. Su SHY2012073026 (HMAS274021, holotype).

Habitat: solitary in the forest.

Specimen examined: CHINA, Yunnan Prov., Dali City, Cangshan, 30 July 2011, collected by H.Y. Su SHY2012073026 (HMAS274021, holotype). China, Yunnan Prov., Tengchong county, Datang, Danlonghe Village, 28 July 2011, collected by G.F. Yang ZRL2011249 (HMAS274019).

Distribution: China.

Notes: the morphological characters of A. litoraloides are similar to A. litoralis in having large and dark brown scales, large spores, discolouring on touching and cutting, and odour. However, the molecular analysis clearly supports them as distinct species.