Agaricus hingganensis R.L. Zhao & B. Cao, sp. nov. 2020
Fungal Names: FN 570669
Holotype: CHINA. HEILONGJIANG: Greater Hinggan, Huzhong, solitary on ground in grassland, 16 Aug 2015, Guojie Li ZRL20151696 (holotype HMAS 280520).
Morphological description
Pileus 70–95 mm wide, convex with subumbonate; surface dry, covered by light brown fibrillose-squamose at disc and background white; edge slightly exceeding. Lamellae free, up to 5 mm broad, crowded, with intercalated lamellulae, pink. Stipe 117–130 × 10–15 mm, cylindrical to slightly clavate, hollow, surface slightly fibrillose below the annulus. Annulus superior, membranous, fragile, white, smooth on the upper surface and floccose on the lower surface.
Context white, unchanging when exposed. Odor of almond. KOH reaction yellow; Schäffer’s reaction reddish orange on pileus and stipe.
Basidiospores 7–8(–8.5) × 4.5–5(–6) μm [x¯= 7.7 × 5 μm, Q = (1.3–)1.5–1.6(–1.7), Qm = 1.6, n = 30], ellipsoid or ovoid, smooth, thick-walled, brown. Basidia 21–25 × 8.5–10.5 μm, 4-spored, rarely 2-spored, clavate or slightly truncate at the apex, hyaline, smooth. Cheilocystidia 13.5–26.5 × 5.5–20 μm, hyaline, simple or sometimes catenulate, consisting of obovoid or broadly ellipsoid elements. Pileipellis a cutis of cylindrical hyphae, 4–16 μm wide, not or slightly constricted at septa, hyaline.
Habitat: on ground in grassland.
Distribution: northeast China.
GenBank Accession: ITS MK617882; 28S MK617794; tef1 MK614390
Notes: Agaricus hingganensis is represented by two Arxan, Yiershi, 23 Aug 2015, Guojie Li specimens from the Greater Hinggan Mountains in northeast China.
Reference: Bin Cao , Mao-Qiang He , Zhi-Lin Ling et al. (2020): A revision of Agaricus section Arvenses with nine new species from China.
Agaricus hingganensis (ZRL20151696, holotype). A. Basidiomes. B. Basidiospores. C. Basidia. D. Pileipellis hyphae. E. Cheilocystidia. Bars: A = 2 cm; B–E = 5 μm.
