Lyophyllum edulis S. M. Tang & S. H. Li, 2025

Lyophyllum edulis S. M. Tang & S. H. Li sp. nov.

Figs 2 A, B View Figure 2 , 3 View Figure 3 , 4 View Figure 4

Etymology.

The epithet “ edulis ” refers to the edibility of this species; locally it is considered a delicacy.

Holotype.

China, Sichuan Province: Jiuzhaigou County, elev. 2,100 m, October 12, 2023, Song-Ming Tang, L 6737 ( HKAS 135644 View Materials !).

Description.

Pileus 3–8 cm diameter, fleshy, fragile, hemispherical, becoming convex with age, smooth on the surface, dry, dark grayish orange (# 8 a 7971) on the center, soft orange (# e 9 c 7 a 7) with margin, subumbonate of center, inflexed of margin; pileus context thick, 0.2–0.3 cm wide, white (# fcfcfc). Lamellae moderately close together, arcuate, subdecurrent to decurrent, broad, white (# fcfcfc), unchanging color when injured, 3–4 tiers, 0.4–0.5 cm wide, edge even or entire. Stipe 3.7–6.9 × 0.8–1.4 cm, cylindrical, grayish orange (# d 9 cdc 2) in the upper, soft orange (# e 9 c 7 a 7) gradually downward, smooth; stipe context white (# fcfcfc), solid, unchanging in color when injured. The odor and taste were not distinctive.

Basidiospores [84 / 2 / 2] 5.1–6.5 (– 8) × 4.6–6.6 μm, (Q = 1.0–1.2, Qm = 1.11 ± 0.05), av. 5.81 ± 0.28 × 5.47 ± 0.38 μm, globose, subglobose to broadly ellipsoid, hyaline, smooth. Basidia 25–39 × 8–11 μm (N = 20), av. 32.7 ± 5.1 × 9.7 ± 1.0 μm, mostly 4 - spored, rarely 2 - spored, sterigmata long 1.8–4.9 μm, sometimes with basal clamp connections, clavate, siderophilous granulations. Subhymenium is composed of moderately thin-walled hyphae, 40–55 μm thick, with 2–3 layers of ovoid, fusiform to narrowly cylindrical hyphae, and 6–8 × 3–5 μm. Hymenophoral trama regular, 120–150 μm wide, consisting of thin and hyaline hyphae, some with clamp connections, narrowly cylindrical hyphal elements, 6–12 μm wide. Cheilocystidia were 21–24 × 4–7 μm in size and av. 22.9 ± 1.3 × 6.4 ± 0.7 μm, narrowly cylindrical or narrowly clavate, thin-walled, and rarely mucronate or rostrate on the apex. Pleurocystidia 24–28 × 4–6 μm, av. 26.3 ± 1.6 × 5.3 ± 0.6 μm, narrowly cylindrical or narrowly clavate, thin-walled. Pileipellis colorless and hyaline in 5 % KOH solution, parallel, thin-walled, almost cylindrical to subcylindrical, filamentous hyphae 4–6 μm wide. Stipitipellis composed of appressed, parallel, thin-walled, hyphae 2–7 µm wide. Clamp connections are present at some septa in the pileipellis, lamellae, and stipitipellis.

Habitat.

Clustered, related to Quercus glauca in broad-leaved forests in Sichuan and Shandong provinces.

Economic value.

Edible, available in local markets.

Additional materials examined.

China • Sichuan Province: Jiuzhaigou County, elev. 2,380 m, October 12, 2023, Song-Ming Tang, paratype, L 6738, HKAS 135645 View Materials ; Shandong Province, Jinan County, elev. 2,210 m, October 11, 2023, Tong Lv, L 6880, HKAS 135646 View Materials .

Notes.

Lyophyllum edulis is similar to L. fumosum , L. subdecastes , L. loricatum , and L. littorale by sharing globose to subglobose basidiospores. However, the stipe surface of L. fumosum is cream to brown and has relatively larger basidia (40–45 × 8–10 µm; Sesli et al. 2015). Lyophyllum subdecastes pileus surface is yellowish-brown or brown to greyish-red, stipe surface is reddish grey to greyish red, and smaller basidiospores (3.9–5.0 × 3.7–5.0 µm; Wei et al. 2023). Lyophyllum loricatum was originally described in Sweden; its pileus surface is reddish-brown to chestnut-brown, and the stipe surface is pale brownish or grey-brown ( Breitenbach 1991). Lyophyllum littorale stipe surface is grey and has smaller basidiospores (4.5–5.5 × 4.5–5.5 µm; Ballero and Contu 1990).

In our multi-locus phylogeny, L. decastes (Fr.) Singer , L. shimeji (Kawam.) Hongo , and L. heimogu S. H. Li are sister to the clade of L. edulis . However, the original description of L. decastes from Sweden has a whitish-greyish stipe ( Breitenbach 1991; Trudell and Ammirati 2009; Davis et al. 2012), and ITS sequence differences between L. edulis ( HKAS 135664 , holotype) and L. decastes (Ld 418) were 1.81 % (10 / 552, including 2 gaps). Lyophyllum shimeji , originally described from Japan as Tricholoma shimeji Kawam. , has a dark grey to grey pileus; ITS sequence differences between L. edulis ( HKAS 135664 , holotype) and L. shimeji (L 2010512377) were 4.89 % (27 / 552, including 2 gaps). Lyophyllum heimogu , collected from Xizang, China, has dark grey to olive pileus and stipe surface yellowish-brown; ITS sequence differences between L. edulis ( HKAS 135664 , holotype) and L. heimogu (L 3026, holotype) were 1.81 % (10 / 552, including 2 gaps). Thus, they were classified as a heterospecific species.