Agaricus purpureofibrillosus Linda J. Chen, R. L. Zhao & K. D. Hyde, Persoonia
Creators: name: Arya, C. P.
name: Pradeep, C. K.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Agaricaceae
Agaricus
Agaricus purpureofibrillosus

description: Agaricus purpureofibrillosus Linda J. Chen, R.L. Zhao & K.D. Hyde, Persoonia 38: 191 (2017) (Fig. 7)
Description:— Pileus 28–49 mm diam., first convex, later plano-convex to applanate with a small broad obtuse umbo or with a shallow central depression; surface reddish grey to dull red (7B2/7B3/8B2/9A2/9B3) with reddish brown to greyish red (9D4/9E4/9E5/10D4) appressed squamules, denser at the disc, sparse towards the margin, dry; margin straight, entire to incised with appendiculate remnants from the partial veil, slightly exceeding the lamellae. Lamellae free, first orange white, then dull red, finally greyish brown to dark brown (5A2/6F5/8C3/8F5/9D3), up to 3 mm wide, crowded with lamellulae of different lengths; edge concolorous to the sides, entire. Stipe 35–65 × 3–6 mm, central, cylindric, curved, hollow, fragile, equal or tapering upwards from a slightly bulbous base; surface white, smooth and glabrous throughout, becoming yellowish on bruising. White mycelial strands present at the base. Annulus superous, simple, membranous, descending, evanescent. Context white, up to 3 mm thick at the pileus disc, soft. Odor of anise.
Macrochemical reactions:—KOH and Schäffer’s reactions positive on fresh basidiomata.
Basidiospores 4.4–5.6 × 2.8–3.2 µm, (avL= 5.01± 0.44, avW= 3.0 ± 0.199), Q= 1.3–1.85, (avQ= 1.65), ellipsoid to oblong, brown, thick-walled, without apical pore. Basidia 12–15.2 × 5.6–8 µm, clavate to broadly clavate, tetrasterigmate, thin-walled, hyaline. Cheilocystidia abundant, thin-walled, simple or rarely septate at base, pyriform, sphaeropedunculate, or broadly clavate, spherical, vesiculose with yellowish granular contents, 10–32 × 8–24 µm. Pleurocystidia absent. Hymenophoral trama regular, hyphae 5.4–27.5 µm wide, thin-walled, constricted at septa, hyaline. Pileal trama interwoven, branched, septate, hyphae 8.8–29.7 µm wide, inflated, thin-walled, hyaline. Pileipellis a cutis, composed of parallel, cylindrical hyphae 4.4–8.6 µm wide, not or slightly constricted at septa, thin-walled with light-brown contents. Stipitipellis composed of parallel, hyaline hyphae, cylindrical, slightly constricted at septa 4–7.7 µm wide, thin-walled, hyaline. Annulus composed of hyaline hyphae, cylindrical 2.3–6.1 µm wide, thin-walled. Clamp connections absent.
Habitat and phenology:—Solitary, or in pairs on humus rich soil; fruiting in April, June, July.
Additional specimens examined:— India, Kerala State, Thiruvananthapuram District, Palode, JNTBGRI Campus: 8.75°N, 77.02°E, elev. 150 m, 03 July 2008, Arya TBGT (M)11278; ibid., 30 April 2010, Arya TBGT (M)13199; ibid., 06 June 2019, Arya TBGT (M)17770; ibid., 13 June 2019, Arya TBGT (M)17807 (OR647596); ibid., 14 June 2019, Arya TBGT (M)17812.
Notes: Originally described from Thailand (Chen et al. 2017), A. purpureofibrillosus is characterized by a slender sporocarp, purplish fibrillose squamulose pileus, small basidiospores, simple sphaeropedunculate to broadly clavate cheilocystidia with yellowish contents, simple annulus and strongly flavescent stipe surface when bruised or rubbed. BLASTn search using the nrITS sequence (680bp) from the present collection showed 99% sequence identity with only three nucleotide difference with A. purpureofibrillosus (JF691542) from Thailand (Chen et al. 2017). Since no substantial morphological and molecular differences were noticed in the Indian collection with the type collection from Thailand, we confirm our collection as A. purpureofibrillosus. It is known only from the type locality until now and this report forms a new phytogeographical record.
description: Published as part of Arya, C. P. & Pradeep, C. K., 2024, Agaricus section Minores: New and noteworthy species from India, pp. 255-273 in Phytotaxa 634 (3) on pages 269-270, DOI: 10.11646/phytotaxa.634.3.5, http://zenodo.org/record/13878928