Leucocoprinus ferrugineus J. Z. Xu, 2025

Zhang, An-Qi, Jin, Ri, Zhang, Xue-chao, Tarafder, Entaj & Xu, Ji-Ze, 2025, Two new species of genus Leucoagaricus and Leucocoprinus (Agaricaceae, Agaricales) from China, MycoKeys 125, pp. 33-49 : 33-49

Leucocoprinus ferrugineus J. Z. Xu sp. nov.

Fig. 3

Diagnosis.

Leucocoprinus ferrugineus differs from Lc. purpurascens by the absence of cheilocystidia, basidiospores amygdaliform, smaller basidia (14.7 – 21.5 × 6.4–9.5 µm) ( Guo et al. 2023) and distinctive ITS, nrLSU, rpb 2, and tef 1 - α sequences and position in the phylogram.

Holotype.

China • Nei Mongol, Hinggan League City, Arxan National Forest Park , on soil, 1 September 2020, J. Z. Xu ( HMJU 745 , holotype) .

Etymology.

The species epithet “ ferrugineus ” is derived from the Latin word “ ferruginous ”, referring to the ferruginous red pileus at the center of the taxon.

Description.

Pileus 12–35 mm diam, convex-lens, mahogany-red (8 E 7) blunt umbo at center and small mahogany-red (8 E 7) squamules in white base color; margin uneven oxide-red (8 E 8). Context white, discoloring to oxide red (8 E 8) when bruised, thick. Lamellae free, white with densely radiating tomato-red (8 C 8) spots, less than 1 mm in width with 1–3 tiers of lamellulae; edge entire. Stipe 35–50 × 2–3 mm, cylindrical with a swollen base, white in the lower part, gradually deepening to fox (8 D 7). Annulus at the upper middle portion of the stipe, white, with a mahogany-red (8 E 7) margin.

Basidiospores [40 / 4 / 2] (5.9 –) 6.8–7.5 – 8.5 (– 8.9) × (4.1 –) 4.3–4.9 – 5.6 (– 6.2) µm, Q = 1.4–1.9, Qm = 1.54, broadly ellipsoid to slightly elongated, without germpore, transparent in 3 % KOH, dextrinoid, with 1 or 2 guttules. Basidia (13.1 –) 14.7–18.1 – 21.5 (– 21.8) × (6.3 –) 6.4–7.9 – 9.5 (– 10.4) µm, 2–4 spored, broadly clavate; sterigmata up to 2.5 µm long, hyaline in KOH. Cheilocystidia (28.0 –) 34.0–44.7 – 59.8 (– 71.2) × (11.1 –) 12.2–16.5 – 21.3 (– 28.2) µm, capitate to subcapitate, smooth and hyaline in KOH. Pleurocystidia absent. Lamellatrama regular, made up of parallel to subparallel, 3.26–12.53 μm wide, hyaline in KOH. Pileipellis a cutis of repent, subcylindrical, radially arranged, occasionally branched, trichodermal, seen hyphae 3.0–13.5 μm wide, transparent in 3 % KOH. Clamp connections absent.

Habitat.

Solitary on the soil in coniferous-broadleaf mixed forest.

Known distribution.

Known only from north-eastern China.

Additional material examined.

Nei Mongol • Hinggan League City, Arxan National Forest Park , on soil, 1 September 2020, J. Z. Xu. ( HMJU 898 )

Notes.

The species is characterized mainly by mahogany-colored squamules at the center, stipe fox-brown in median to lower portions, deepening in color toward the base, annulus white with a mahogany-colored margin, context turns oxide red upon injury, and the spores are ellipsoid and ITS, nrLSU, rpb 2, tef 1 - α sequence analyses, the present species cluster with members of the Lc. beijingensis and Lc. purpurascens signifies its position. Among morphologically related species, the present specimen is somewhat similar to species such as Lc. purpurascens , Leucocoprinus lahorensis Asif , Saba & Vellinga, Leucocoprinus antillarum Justo, Bizzi, Angelini , Leucocoprinus brunneocanus , Leucocoprinus brunneus . Among morphologically related taxa, Lc. purpurascens differs in lacking cheilocystidia and pileipellis hyphae, which are typically yellowish-brown ( Guo et al. 2023). Leucocoprinus antillarum has larger spores, cheilocystidia that are subfusiform, and basidiomata that are uniformly white. Leucocoprinus brunneocanus Asif , Saba & Vellinga has gray squamules of pileus; context un-discoloring when bruised; and cheilocystidia sometimes constricted or curved ( Asif 2024). Leucocoprinus brunneus differs by having a thicker stipe; cheilocystidia are smaller and clavate.

Figures

Figure 3. Leucocoprinus ferrugineus (HMJU 745, holotype). A, B. Basidiocarps; C. SEM images of basidiospores; D. Basidiospores; E. Basidia; F. Cheilocystidia; G. Pileipellis. Scale bar: 2 cm (A, B); 2 µm (C); 5 µm (D, E); 10 µm (F, G).