Leucoagaricus purpurascens T. Guo & Z. W. Ge, 2023

Guo, Ting, Ma, Yun-Rui, Yang, Rui-Heng, Ge, Zai-Wei & Bao, Da-Peng, 2023, Leucoagaricus purpurascens, a new species from eastern China based on morphological characteristics and molecular evidence, Phytotaxa 584 (3), pp. 197-206 : 202

Leucoagaricus purpurascens T. Guo & Z. W. Ge , sp. nov. FIGURES. 2–3

MycoBank:—MB 845096

Etymology:—“ purpurascens ” means becoming purple, referring to the basidiomata turning purple upon drying.

Diagnosis: Similar to Leucoagaricus viriditinctus but differs in the purple changes of basidiomata when dried, larger basidiospores, and the absence of cheilocystidia.

Holotype:— CHINA. Shanghai: Sheshan National Forest Park , on the ground in an evergreen broad-leaved forest, elev. 40 m, 22 September 2020, T. Guo 2137 ( HKAS 123023!). GenBank: ITS = OM987458; LSU = OM987455.

Description: — Basidiomata ( FIGURE 2 ). Pileus 1–2.5 cm diam, when young campanulate, expanding to planoconvex to applanate, umbonate; center light brownish (7C3) to dark brown-red (8E4), elsewhere with light brownish squamules on the whitish (9A1) background; Context thin, whitish (9A1); discolours purplish (16B2) to purple (16A4) on drying. Lamellae free, whitish to creamy (6A2), crowded, with lamellulae in 1–2 tiers, edge even; discolours purplish (16B2) to purple (16A4) on drying. Stipe 2.5–5 × 0.1–0.2 cm, whitish (9A1), slightly attenuate upwards, sometimes slightly curved at the base, smooth, hollow, not brittle; stipe context white; Annulus present, sometimes disappearing, with light brownish (6C5) superior edge, membranous. Odor none. Taste not recorded.

Basidiospores ( FIGURE 3 ) [71/3/3] 8.0–10.0 (10.5) × (4.0) 4.5–6.0 μm (mean 9.2 ± 0.7 × 5.1 ± 0.5 μm), Q = (1.5) 1.6–2.0, Q av = 1.79 ± 0.15, amygdaliform, (sometimes ellipsoidal to oblong) in side view, ovoid in front view, hyaline, smooth, slightly thick-walled (about 0.5 μm), dextrinoid, without germ pore, metachromatic in Cresyl Blue. Basidia (24.0) 24.5–31.0 (32.0) × (9.0) 9.5–10.5 (11.0) μm, clavate, four-spored; sterigmata up to 3 μm. Cheilocystidia and pleurocystidia not observed. Lamella trama subregular, made up of slightly inflated subcylindrical hyphae, hyaline, thin-walled. Pileus covering a cutis with radially arranged and sometimes branched repent hyphae, subcylindrical, 7.5–12.5 μm diam, occasionally with brownish yellow pigments on the hyphal wall and in vacuoles. Stipe covering a cutis made up of cylindrical hyphae and elements, colourless, (4) 7–10 µm wide. Clamp connections not observed.

Habitat and distribution:—Gregarious or scattered in the subtropical evergreen broad-leaved forest; currently only known from the type locality.

Additional specimens examined:— CHINA. Shanghai City, Sheshan National Forest Park, on the roadside in a subtropical evergreen broad-leaved forest, elev. 35 m, 4 August 2021, T. Guo 2323 (HKAS 123024); same locality, 4 August 2021, T. Guo 2324 (HKAS 123025) .

Figures

FIGURE 2. Basidiomata of Leucoagaricus purpurascens. a. Basidiomata (HKAS 123023, holotype!). b. Dried specimens (HKAS 123023). Bars = 1 cm.

FIGURE 3. Microscopic characteristics of Leucaoagricus purpurascens (HKAS 123023, holotype). a. Basidia; b. Basidiospores; c. Pileipellis.