Agaricus patris

Agaricus patris Linda J. Chen, Callac, K.D. Hyde & R.L. Zhao

Index Fungorum number: xxx, Facesoffungi number: FoF 02290.

Pileus 4.5–5 cm diam, 3–4 mm thick at disc; convex to applanate; surface dry, covered with purplish brown to reddish brown or dark purple fibrillose scales, dense at disc and progressively sparse towards the margin, on a greyish white background; no discoloration when rubbed. Margin incurved, then becoming straight, shortly exceeding the lamellae, often with appendiculate remains of the annulus. Lamellae free, crowded, 4 mm broad, with intercalated lamellulae, ventricose, pink to light brown, finally dark brown. Stipe 45–68 × 5–7 mm (8–15 mm at base), cylindrical with a bulbous base, fistulose, surface above the ring smooth, below the ring tomentose, white, flavescent or orange-ochre when rubbed. Annulus simple, membranous, superous, white, fragile. Context firm, white, somewhat flavescent when cut. Odour of almonds. Spores (5.5–)5.8–6.2(–6.5) × (3.3–)3.5–4.0(–4.2) µm, (x = 6 ± 0.16 × 3.7 ± 0.15 µm, Q = 1.49–1.72, Qm = 1.58 ± 0.01, n = 20), ellipsoid, rarely oblong, smooth, brown, thick-walled. Basidia 14–22 × 6–7 µm, clavate, hyaline, smooth, 4-spored, rarely 2-spored. Cheilocystidia 16–34 × 7–13 µm, simple, clavate to broadly clavate or sphaeropedunculate, hyaline or sometimes with yellowish pigments, smooth. Pleurocystidia absent. Pileipellis a cutis composed of hyphae of 6–13 µm wide, cylindrical, often with brownish pigments, constricted at the septa. Macrochemical reactions — KOH reaction positive, yellow. Schäffer’s reaction positive, reddish on dry specimen. (Figs. 1–2)

Notes: Agaricus patris is morphologically characterized by having a pileus surface covered with fibrillose scales, of variable colour ranging from purplish brown to reddish brown or dark purple, spores 6 × 3.7 μm on average, and simple cheilocystidia.

Habitat: Solitary, on soil of roadside.

Material examined: THAILAND, Chiang Mai Prov., Mae Pong Nature Trail, 3 June 2012, J. Chen, LD201224 (holotype MFLU2012-0868; isotype HMAS279139); Chiang Mai Prov., MRC, 13 Sept. 2006, R.L. Zhao, ZRL3101 (BBH19617, HMAS279143).