Hymenagaricus pakistanicus M.F. Syed & M. Saba, sp. nov. Figs. 3–5

MycoBank:—MB846346

Etymology:—“pakistanicus” refers to Pakistan, the country where the type was collected.

Diagnostic characters:— H. pakistanicus sp. nov. is distinguished from all other known taxa by a pileus with striate margin, and the absence of a membranous annulus.

Holotype:— PAKISTAN. Khyber Pakhtunkhwa province, district Karak, Tehsil Takht-e-Nasrati, Ziarat Siraj Khel, 70.40°– 71.30°N 32.48°– 33.23°E, elevation 556 m, gregarious on sandy clay soil, near Phoenix dactylifera L., Zizyphus spp (L.) Meikle, 28 August 2020, leg. M. F. Syed, coll. FAK195 (ISL-F0010). GenBank ITS accession number OP082404.

Description:— Basidiomata small to medium-sized. Pileus 2.4–3.0 cm in diameter, hemispherical to convex when young, plano-convex to applanate at maturity; white to pinkish white; central disk dark brown (7.5YR1/2#2B180E) with numerous small dark olive brown (2.5Y2/4#422D09) squamules on a light brown (5YR6/4#B78B78) background; margin striate, sometimes with floccose remnants (Fig. 3A–E). Lamellae free, dark reddish orange (7.5YR4/8#9E4540), regular, distant, with denticulate edge, intercalated with lamellulae, (Fig. 3D). Stipe 3–3.2 × 0.29–0.3 cm, central, cylindrical, with or without bulbous base, fistulose, equal, texture rough, reddish brown, sometimes covered with white fine squamules or fibrils. (Fig. 3C–E). Annulus absent. Context slightly reddening when cut or injured. Spore print dark brown. Smell indistinct. Taste unknown.

Basidiospores [60/3/4] (4.6–)4.9–6.2(–6.5) × (3.1–)3.3–4.9(–5.2) µm, Q = 1.13–1.80, Qav = 1.44, avl × avw = 5.7 × 3.9 μm, subglobose to broadly ellipsoid, smooth, thick-walled, yellowish brown to dark brown, apiculate, with central guttule (Figs. 4A, 5A). Basidia 15.6–24.1 × 5.2–10.4 µm, tetra-sterigmate (Fig. 4C), clavate, smoothwalled; sterigmata 2.6–2.8 µm long (Fig. 5B). Cheilocystidia 15.6–33.8 × 5.2–10.4 µm, clavate to narrowly clavate, sometimes cylindrical to broadly cylindrical, smooth, thin-walled (Figs. 4D, 5C). Pleurocystidia absent. Hymenophoral trama composed of regular to subregular hyaline hyphae, 2.6–7.8 µm wide (Fig. 4C). Pileal squamules composed of epithelial, hymeniform cells, thin-walled subglobose to irregular cells, encrusted with brownish pigments, 5.2–10.4 × 2–4 µm (Figs. 4B, 5D). Pileipellis a cutis of parallel, interwoven, loosely arranged, thin-walled hyphae, 4.6–10.4 µm diam, septate, hyaline, branched (Fig. 5E). Stipitipellis composed of hyphae 5.2–11.7 µm diam, regular, parallel, septate, hyaline, branched. Clamp connections absent (Fig. 5F).

Habit, habitat and distribution:—Caespitose, gregarious on sandy clay soil, saprotrophic, near Phoenix dactylifera and Zizyphus spp, collected from Tehsil Takht-e-Nasrati, Ziarat Siraj Khel, Karak, July and August. Currently only known from Khyber Pakhtunkhwa province in Pakistan.

Additional specimens examined:— PAKISTAN. Khyber Pakhtunkhwa province, district Karak, Tehsil Takht-e-Nasrati, 70.40°– 71.30°N 32.48°– 33.23°E, elev. 556 m, on ground, 24 July 2021, leg. M. F. Syed, coll. FAK196 (ISL-F0011), GenBank accession number OP 082405 ; district Karak Tehsil Takht-e-Nasrati, 70.40°– 71.30°N 32.48°– 33.23°E, elev. 556 m, on ground 22 August 2021, leg. M. F. Syed, coll. FAK197 (ISL-F0012), GenBank accession number OP082406; District Karak, Tehsil Takht-e-Nasrati, 70.40°– 71.30°N 32.48°– 33.23°E, elev. 556 m, on ground 28 July 2022, leg. M. F. Syed, coll. FAK198 (ISL-F0013) .