Agaricus brunneosquamulosus Linda J. Chen, R.L. Zhao, K.D. Hyde & Callac, in Chen et al., Phytotaxa 192:154 (2015)
Index Fungorum number: IF 808173; MycoBank number: MB 808173; Facesoffungi number: FoF 14219; Fig. 1
Holotype –MFLU 12-0881
Macroscopic characters –Basidiomata small to medium, thick and fleshy. Pileus 43–84 mm diam., convex to planoconvex when young, later applanate with a flat disc; surface white to off white with brownish orange to brown (5F7/6C3/6D3/7E4) appressed squamules arranged in a more or less concentric fashion expect at the disc which is entire; scales may be washed off during heavy rain especially near margin to expose the greyish red (9B4) context below, dry; margin straight, wavy, variously incised, appendiculate with remnants of the partial veil. Lamellae free, reddish grey to dull red (7B2/7B3/7C2/8B3/8C3) when young becoming eye brown (7F6) when mature, up to 6 mm wide, crowded with lamellulae of different lengths; edge concolorous to the sides, entire. Stipe 39–93×4–7 mm, central, cylindric, stuffed to hollow, equal with a subclavate to clavate base; surface white becoming brown on handling; white fine squamules present below the annulus and glabrous above the annulus; squamules easily vanishing on handling to appear smooth. White mycelial rhizoids present. Annulus superior, double, white, membranous, pendant, flaring, with floccose squamulose on lower side. Context white, turn brownish on exposure, up to 6 mm, thick, soft, fleshy. Odor aniseed like. Taste mild.
Microscopic characters –Basidiospores 4.8–6×3.2–4 μm diam., (avL = 5.28 ± 0.38 μm, avW = 3.54 ± 0.28), Q =1.3–1.6 μm, (avQ =1.44±0.084), ellipsoid, smooth, brown, thick-walled. Basidia 15–24 × 6–10 μm, clavate, hyaline, tetrasporic, thin-walled, hyaline. Lamella edge sterile with crowded cheilocystidia. Cheilocystidia 12–40 × 4.8–20 μm, clavate, broadly clavate, vesiculose, subglobose with one to two basal septa in some, thin-walled, hyaline. Pleurocystidia absent. Hymenophoral trama regular composed of cylindrical hyphae, 4–16 μm diam., thin-walled, hyaline. Subhymenium pseudoparenchymatous. Pileal trama composed of multiseptate, inflated hyphae, 4–28 μm diam., thin-walled, hyaline. Pileipellis an interrupted epicutis with erect to suberect hyphae, 4–14 μm diam., with brown vacuolar contents, slightly constricted at the septa. Stipitipellis a cutis, composed of multiseptate cylindrical hyphae, 4–16 μm, thin-walled, hyaline. Annulus lower surface composed of branched cylindrical interconnected hyphae 4–12 μm wide, mixed with easily disarticulating shorter, wider hyphae up to 16 μm wide, thin-walled, hyaline. Oleiferous hyphae present. Clamp connections absent.
Macrochemical reactions –Schäffer’s and KOH reactions negative.
Habitats and distribution –solitary to scattered on soil, known from Thailand (type collection) and Kerala State, India.
Materials examined – India, Kerala State, Thiruvananthapuram District, Palode, JNTBGRI campus, 8.75° N, 77.02° E, elev. 150 m, 13 May 2019, TBGT(M)17808; ibid. 17 June 2019, TBGT(M)17822; 18 June 2019, TBGT(M)17828; 3 September 2019, TBGT(M)17954; 13 May 2020, TBGT(M)18054; 26 November 2020 TBGT(M)18440; Kottayam District, Chittadi, 9.54° N, 76.86° E, elev. 67 m, 1 June 2022, TBGT(M)18847.
GenBank numbers –ITS: OP518433, OP518480, OP518603.
Notes – Agaricus brunneosquamulosus Linda J. Chen, R.L. Zhao, K.D. Hyde & Callac, is characterized by a set of features such as medium-sized basidiomata, white pileus with concentrically arranged brownish squamules, double annulus with floccose squamules on lower surface, clavate to pyriform cheilocystidia and negative KOH and Schaffer’s reaction. The species was originally described from Thailand (Chen et al. 2015a), and the Indian collection is similar to the type description both morphologically and molecularly. ITS sequence (692 bp) of Indian collection shows 99% sequence identity with A. brunneosquamulosus (KJ540968) with only three nucleotide differences. Slightly larger basidiomata, smaller basidiospores and abundant cheilocystidia are the changes observed in the present collection from the type description. As no major differences were noticed in the Indian material, we confirm the Indian collection as A. brunneosquamulosus (Fig. 2).
Figure 1 – Agaricus brunneosquamulosus (TBGT17828). a Habit. b Gill view. c Sectional view. d Basidiospores. e Cheilocystidia. f Annulus. Scale bars: a–c=10 mm; d–f=10 μm
Figure 2 – Phylogeny of species of Agaricus section Brunneopicti generated from ML analysis of ITS sequence data rooted with Agaricus bohusii. Bootstrap values (ML, ˃50%) are indicated above/below branches. Taxa from Kerala, India used in the present study are in bold