Pseudosperma parvisporum Abbas, Naseer & Khalid, 2025

Abbas, Ali, Naseer, Arooj & Khalid, Abdul Nasir, 2025, Pseudosperma parvisporum sp. nov., (Inocybaceae, Basidiomycota) from Pakistan, Phytotaxa 684 (1), pp. 117-128 : 122

Pseudosperma parvisporum Abbas, Naseer & Khalid , sp. nov.

MycoBank no.: MB 849055 ( Figures 1–2 )

Etymology:—The specific epithet ‘ parvisporum’ is a Latin word, referring to the smaller size of basidiospores.

Diagnosis: — Pseudosperma parvisporum is diagnosed by its campanulate, becoming plano-convex to convex at maturity, brown umbo, brownish golden to yellow fibrils and up to 4.5 cm diam. pileus; cylindrical, up to 8 cm long stipe; smaller basidiospores (8.86–10.86 × 5.06–6.2 μm); oblong to utriform (34.3–51.5 × 9.6–14.6 μm) cheilocystidia and occurrence of fusiform to lageniform caulocystidia.

Holotype: — PAKISTAN, Khyber Pakhtunkhwa Province, Abbottabad, Shimla Hill , 2206 m a.s.l., solitary, on soil, on pine needles close to Pinus roxburghii Sarg. , 22 nd August 2022, Ali Abbas & Arooj Naseer, SH-38 (holotype, LAH37825 ; GenBank ITS-OR075111, LSU-OR075110 ).

Description: — Basidiomata medium sized. Pileus 3.4–4.5 cm diameter, campanulate with slight umbo in young becoming plano-convex to convex with prominent umbo in maturity, cracked, ragged or splitting with age; brown (7.5YR 4/3) umbo with brownish golden to yellow (10YR 8/6) fibrils spread on, creamy white (10YR 8/1) context becoming dark brown (7.5YR 3/2) in center and yellowish-brown (10YR 5/4) disc with age; surface radially, fine fibrillose in young becoming wide fibrils to rugulose with age; margins incurved, straight, uneven ruptured. Lamellae adnexed to adnate, subdistant, creamy whitish (10YR 8/1) to brown (10YR 4/3), even, smooth becoming crenate edge. Lamellulae present, regular, 1–2 tiers alternate with lamellae, concolorous with lamellae. Stipe 7.7–8 × 0.54– 0.5 cm, central, smooth, cylindrical, hollow, pruinose only at apex, longitudinally striations; white (10YR 8/1) apex, golden yellow (10YR 8/6) with creamy white (10YR 8/1) base in young becoming brown (10YR 4/3) with white (10YR 8/1) hollow base.

Basidiospores [200/2/2] (8.86–)9.02–10.43(–10.86) × (5.06–)5.2–5.96(–6.2) μm, avL × avW = 9.6 × 5.5 μm, Q= 1.57–1.85, avQ= 1.7; ellipsoid to indistinctly phaseoliform, apices obtuse, apiculus indistinct, yellow to brown in 5% KOH, surface smooth, thick-walled, guttulate. Basidia (22.5–)23.3–44.5(–46.8) × (9.3–)10.0–14.6(–15.5) μm, avL × avW = 34.6 × 12.8 μm, Q= 2.40–3.26, avQ=2.8, clavate to broadly clavate, hyaline in 5% KOH, thin walled, guttulate. Cheilocystidia (34.3–)36.4–50.7(–51.5) × (9.6–)9.7–14.0(–14.6) μm in size, avL × avW= 43.5 × 11.8 μm, oblong to utriform, clavate, obtuse at apex, occur in groups, abundantly, hyaline in 5% KOH, smooth, thin walled. Pleurocystidia absent. Pileipellis a cutis, 4.9–17.3 μm breadth, avW= 10.3 μm, hyphae branched and compactly arranged, septate, terminal cells forming an intricate trichoderm to trichohymeniderm, 25.1 × 4.7 μm, hyaline in 5% KOH, smooth, thin-walled. Stipitipellis 4.9–24.6 μm wide, avW= 12.3 μm, regular to subregular, hyphae septate, unbranched, hyaline in 5% KOH, smooth, thin walled. Caulocystidia 31.7–41.2 × 8.3–10.8 μm, avL × avW= 38.7 × 9.7 μm, narrowly fusiform to lageniform, less frequent, hyaline in 5% KOH, thin walled. Clamp connections observed in all tissues.

Additional Material Examined:— PAKISTAN, Khyber Pakhtunkhwa province, Mansehra, Shimla Hills, 2206 m a.s.l., solitary, on the forest floor in stands of Pinus roxburghii , 12 th July 2022, Ali Abbas & Arooj Naseer, SH-34 (LAH37826. GenBank ITS-OR075124).

Habit and Distribution: — Solitary on the forest floor in stands of Pinus roxburghii ( Pinaceae ). Currently, it is known from Mansehra district, Khyber Pakhtunkhwa, Pakistan only.

Figures

FIGURE 1. Morphology of Pseudosperma parvisporum sp. nov.A–E. Basidiomata B, D, E (holotype—LAH37825) in its natural habitat. (Scale Bar: A–C=1.2 cm; D–E= 1 cm).

FIGURE 2. Anatomy of Pseudosperma parvisporum sp. nov. A. Basidiospores; B. Basidia; C. Cheilocystidia; D. Caulocystidia; E. Pileipellis. (Scale bar: A–E = 4.85 μm).