Clitolyophyllum paraumbilicatum Yan C. Li & P. Lyu, 2025

Clitolyophyllum paraumbilicatum Yan C. Li & P. Lyu , sp. nov. ( FIGURE 2 View FIGURE 2 , 3 View FIGURE 3 )

MycoBank: 857566

Etymology: —The epithet “ paraumbilicatum ” refers to its similarity to C. umbilicatum .

Holotype: — CHINA. Yunnan Province: Lijiang City, Yulong Naxi Autonomous County, Laojun Mountain , 99 Longtan , alt. 3403 m, 99.7792°E, 26.6544°N, 29 August 2023, Yan-Chun Li 5379 ( KUN-HKAS 145691 ). GoogleMaps

Diagnosis: — Clitolyophyllum paraumbilicatum differs from other species of this genus in its relatively small beige-brown to dark brown pileus, a central and slender stipe measuring 30–85 × 3–6 mm, broadly ellipsoid to ovoid or pyriform basidiospores measuring 6–10 × 3.5–5.5 μm, and relatively narrow basidia measuring 21–30 × 4–7 μm.

Description: —Basidiomata omphalinoid. Pileus 21–42 mm in diam., depressed in the center, beige-brown (2B3) to dark brown (5E8), dull when dry, darker towards the center; surface nearly glabrous, hygrophanous; margin slightly undulating, irregularly crenate to entire, radially striate, white (1A1) to wheat-colored (4B2), translucent when moist. Context thin, translucent, unchanged in color when injured. Lamellae decurrent, thin, shallow towards margin, whitecream (5A1) to light cream (3A2), with numerous lamellulae; edge entire. Stipe slender, 30–85 × 3–6 mm, central, cylindrical to flattened, equal or slightly tapering towards apex, hollow, concolorous with pileal surface, longitudinally striate; surface covered with white (1A1) to white-smoke (5B2) filamentous or patchy appendages.

Basidiospores [80/4/2] 6–10 × 3.5–5.5 μm, Q = 1.20–2.13 (2.86), Q m = 1.67 ± 0.17, broadly ellipsoid to ovoid or pyriform, thin-walled, smooth, inamyloid, nondextrinoid, hyaline in KOH. Basidia 21–30 × 4–7 μm, narrowly clavate to subcylindrical, 4-spored, hyaline in KOH. Hymenophoral trama regular, consisting of subcylindrical, subinflated, thin-walled, frequently branched, 2–17 μm wide hyphae, hyaline in KOH. Pileipellis subrepent, made up of interwoven filamentous hyphae; hyphae cylindrical to subinflated, 2–17 μm wide, thin-walled, yellowish to hyaline in KOH; terminal cells 32–45 × 2–4.5, thin-walled, flexuose to cylindrical or irregularly branched, occasionally with several excrescences or weakly coralloid. Stipitipellis made up of longitudinally arranged hyphae; hyphae cylindrical, parallel, frequently branched, thin-walled, nondextrinoid, 3.5–19 μm wide, faintly olivaceous in KOH; terminal cells flexuose to cylindrical or irregularly branched, sometimes with several excrescences. Hyphal system monomitic. Clamp connections present.

Additional specimen examined: — CHINA. Yunnan Province: Lijiang City, Yulong Naxi Autonomous County, Laojun Mountain, Liming, alt. 3033 m, 99.5807° E, 26.9281° N, 26 August 2023, Yan-Chun Li 5094 (KUN-HKAS 145692).

Habitat, ecology and distribution: —Solitary to gregarious, growing on the ground in mixed forests dominated by plants of the families Pinaceae ( Picea sp. ) and Fagaceae ( Quercus sp. ). Currently known from southwestern China.