Agaricus bingensis Heinem., Bull. Jard. Bot. État Bruxelles 26: 72 (1956)

Index Fungorum number: IF 292245; MycoBank number: MB 292245; Facesoffungi number: FoF 14218; Fig. 1

Holotype – BR3052

Macroscopic characters – Pileus 67–92 mm diam., convex when young, later plano-convex to applanate on maturing with or without an umbo; surface dry, chalky white when young with concolorous punctiform squamules, washed off during rain to appear smooth and glabrous, developing a brownish tinge towards margin during heavy rain in old basidiomata; margin appendiculate with remnants of the partial veil, entire to variously incised, exceeding the lamellae. Lamellae free, crowded, up to 7 mm wide, with lamellulae of different lengths, pale red (7A3/8A3) to dark brown (7F7/8F8/9F5); edge concolorous with the sides, entire. Stipe 55–90 × 10–15 mm, central, cylindrical, hollow, brittle, tapering upwards from a bulbous base; surface chalky white, smooth and glabrous above the annulus, punctiform squamules below the annulus, vanishing on handling or during heavy rain. White mycelial strands present at the base. Annulus superior, white, pendant, easily evanescent, upper surface smooth, lower side floccose squamulose. Context white become brownish on bruising, up to 9 mm thick at the pileal disc, fleshy, white. Odor strong of anise.

Microscopic characters – Basidiospores 7.6–10.2×4.9–6 µm, (avL=8.6±0.7, avW=5.47±0.31), Q= 1.5–2 (avQ = 1.58 ± 0.09), ellipsoid to oblong, smooth, brown, thick-walled, without apical pore. Basidia 22–28×7–9 µm, 4-spored, rarely 2-spored, clavate, thin-walled, hyaline. Lamella edge sterile with abundant cheilocystidia. Cheilocystidia 14–46.5×6–21 µm, simple, cylindrical, cylindro-clavate, pyriform, clavate, globose, thin-walled, hyaline. Pleurocystidia absent. Hymenophoral trama regular, hyphae 3–7 µm wide, thin-walled, hyaline. Subhymenium pseudoparenchymatous. Pileal trama interwoven, 8–13 µm, cylindrical to inflated, thin-walled, hyaline. Pileipellis a cutis, composed of parallel, cylindrical hyphae 3–9 µm, not or slightly constricted at the septa, thin-walled, hyaline. Stipitipellis a cutis composed of parallel, hyaline hyphae 4.3–10 µm wide, thin-walled, hyaline. Annulus composed of parallelly arranged cylindrical septate hyphae, not or slightly constricted at the septa, 4–7.6 µm wide, thin-walled, hyaline and some broad elements up to 21.3 µm wide. Clamp connections absent.

Macrochemical reactions – Schäffer’s and KOH reactions negative on dried basidiomata.

Habitat and distribution – solitary on soil in grassland, known from Africa: Bénin, Democratic Republic of the Congo, Togo, Uganda (Chen et al. 2015a) and Kerala State, India

Materials examined – India, Kerala State, Thiruvananthapuram district, Eanikkara, 8.56° N, 76.97° E, elev. 18 m, 26 April 2011, TBGT(M)13568; ibid. Varkala 8.76° N, 76.72° E, elev. 30 m, 18 May 2021, TBGT(M)18562; 18 May 2021, TBGT(M)18563; 19 May 2021, TBGT(M)18564; 20 May 2021, TBGT(M)18568; Govt. College for Women Campus 8.49° N, 76.95° E, elev. 10 m, 1 July 2022, TBGT(M)18888.

GenBank number – ITS: OP518683.

Notes – Agaricus bingensis Heinem., was introduced and described by Heinemann (1956) from Binga, Democratic Republic of the Congo and placed in the section Brunneopicti based on morphology and negative Schäffer’s reaction. This species is characterized by medium to large basidiomata with punctiform squamules on the pileus, large basidiospores (8.3–10 × 5.1–5.7 μm), simple, pyriform, clavate, globose cheilocystidia and pileipellis a cutis. The ITS sequence of our collection is identical to the Benin collection of Agaricus bingensis (KJ540954). Apart from the slightly smaller basidiomata (67–92 mm diam.) and larger cheilocystidia (14–46.5 × 6–21 µm) of our collection, no significant morphological differences were observed with the type collection.

Figure 1 – Agaricus bingensis (TBGT13568). a, b Habit. c Gill view. d Basidiospores. e Cheilocystidia. f Annulus. Scale bars: a–c=20 mm, d–f=10 μm