Pseudosperma quercinum Naseer & Jabeen, 2023

Naseer, Arooj, Jabeen, Sana, Ashfaq, Ammara, Akbar, Mahrukh, Hussain, Syed Iftikhar & Khalid, Abdul Nasir, 2023, Pseudosperma quercinum sp. nov. (Inocybaceae) from the Himalayan forests of Pakistan, Phytotaxa 622 (4), pp. 260-270 : 262-267

Pseudosperma quercinum Naseer & Jabeen , sp. nov. ( Figure 3 & 4 )

MycoBank no.: MB 849661

Etymology:—The specific epithet “quercinum ” refers to its habitat in oak forests.

Holotype:— PAKISTAN. KHYBER PAKHTUNKHWA province, Kurram district, Parachinar, 22 August 2019, Arooj Naseer , (holotype PC-93; LAH35232 ; GenBank MZ314058 for ITS; MZ314078 for LSU).

Diagnosis:—Differs from Pseudosperma umbrinellum by the campanulate to conico-convex pileus with dark brown umbo and yellow-brown fibrillose streaks on creamy white context, a cylindrical stipe with fibrillose, furfuraceous, or almost flocculose apex, ellipsoid to phaseoliform (11.9 × 6.3 µm) basidiospores, and clavate to cylindrical cheilocystidia.

Description:— Basidiomata medium-sized. Pileus 3–3.8 cm wide, campanulate to sub-conical, later conico-convex, umbonate, dark brown (7.5R 3/2) at umbo, with yellow-brown (7.5YR 4/6) fibrillose streaks on creamy white context (10Y8/2), dark brown (7.5R 3/2) patches along margins, surface fibrillose, margin striate, creamy white (10Y8/2). Lamellae crowded, adnexed to sinuate, first creamy white (10Y8/2), light silvery brown (10YR 7/2) when mature, edges fimbriate. Lamellulae alternating with lamellae. Stipe 4.3–5.5 × 0.6–0.8 cm, white (5B 9/2) with brown (5Y 5/4) and dark brown tinge at center, cylindrical, central, fibrillose, apex fibrillose, furfuraceous, or almost flocculose, surface dry, white flocculose, hollow, squamulose, base non bulbous and curved. Odor mild, sweet, like honey.

Basidiospores [100/3/3] (8.8–)8.9–13.8(–14.5) × (5.1–)5.6–6.9(–7.1) µm, avl × avw = 11.9 × 6.3 µm, Q = 1.5–2.1, Qav = 1.9, ellipsoid, phaseoliform, guttulate, apiculus small and indistinctive, pale brown to olive greenish in 5 % KOH, thick-walled. Basidia 18.4–32.3 × 8.9–12.7 µm, avl × avw = 26.9 × 10.9 µm, clavate, hyaline in 5 % KOH, thin-walled, 4-sterigmata. Cheilocystidia 18.8–41.6 × 9.8–25.7 µm, avl × avw = 32.2 × 16.2 µm, numerous, narrowly clavate, hyaline in 5 % KOH. Pleurocystidia absent. Pileipellis a cutis of cylindrical hyphae, 5.4–15.8 µm diam., avw = 9.8 µm, septate, branched, hyaline in 5 % KOH. Stipitipellis a cutis of cylindrical hyphae, 3.4–9.9 µm diam., avw = 6.9 µm, septate, branched, hyaline in 5 % KOH. Clamp connections present in all tissues, abundant.

Additional materials examined:— PAKISTAN. Khyber Pakhtunkhwa, Swat district, Malam Jabba valley, 1950 m asl., under Quercus incana Roxb. [= Q. oblongata D. Don ] in mixed coniferous forest, 10 August 2016, Sana Jabeen MJ1630 (LAH35233!; GenBank MZ314059 for ITS; MZ314079 for LSU. Kurram district, Parachinar, 31 July 2018, Arooj Naseer, PC61; (LAH37418!; GenBank OP303370 for ITS).

Habitat and distribution:—Solitary on rich loamy soil under Quercus spp . in Kurrum district and Swat district, Khyber Pakhtunkhwa, Pakistan.

Figures

FIGURE 3. Basidioma of Pseudosperma quercinum LAH35232 (holotype) in its natural habitat. A–D. Basidioma. Scale bars =1 cm. Photos by: Arooj Naseer.

FIGURE 4. Microscopic structures of Pseudosperma quercinum LAH35232. A: Basidia; B: Basidiospores; C: Cheilocystidia; D: Pileipellis; E:Stipitipellis. Scale bars:A = 7 µm, B = 5.5 µm, C = 8 µm, D = 18 µm, E = 17 µm. Drawings by: Arooj Naseer.