Taxonomic and phylogenetic evidence reveal a new species and a new record of the genus Marasmius (Marasmiaceae) from Pakistan Author Asif, Muhammad Author Maula, Fazli Author Saba, Malka Author Akram, Wajahat Author Raza, Mubashar text Phytotaxa 2024 2024-04-30 646 1 32 46 http://dx.doi.org/10.11646/phytotaxa.646.1.2 journal article 10.11646/phytotaxa.646.1.2 1179-3163 13215142 Marasmius pakistanicus M. Asif, Saba , & M. Raza , sp. nov. ( Figs. 2 , 3 ) MycoBank: MB852490 Etymology:—The specific epithet “ pakistanicus ” refers to the country from where the type specimen was collected. Diagnosis:—Differs from Marasmius ypyrangensis due to its small orange pileus with a grooved surface, creamy lamellae, lacrymoid to subcylindrical basidiospores, broadly clavate cheilocystidia, and a hymeniderm pileipellis composed of inconspicuous or broadly clavate elements. Holotype :— PAKISTAN . Punjab province , Pirowal Reserve Forest , Khanewal district ; 30°34′34″ N, 71°98′48″ E; alt. 136 m elev., on grass twigs, 27 July 2022 , Muhammad Asif, SP-56 , ( LAH38018 ). GenBank accession: ITS = PP051300; 28 S = PP051304 . Description:— Basidiomata tiny in size. Pileus 3–8 mm in diam., hemispherical at early age becoming convex to plane at maturity with a tiny apical papilla in a small umbilicus, yellow-orange (7.5YR7/8) when young becomes light yellow-orange (7.5YR8/4) with age, fragile, surface radially rugulose, sulcate or grooved on the back of lamellae that are not much deep, context thin, dry and dull, margins smooth when young become undulating at maturity, rarely raptured at maturity. Lamellae adnate, creamy (5Y 9/4) to pale yellow (2.5Y8/3), distant, narrow to broad, edges smooth to eroded, margins entire, lamellulae absent or rarely present. Stipe centrally attached, 21–35 × ˂ 1 mm , white (7.5YR8/1) to whitish near pilus, becoming dull orange (7.5YR7/4) towards base, un-equal, bent or curved from middle, cylindrical to compressed, solid, thin, dry, and dull, context very thin, slightly bulbous base. Annulus absent. Basidiospores [50/2/2], (7.1) 7.9–9.9 (10.4) × (3.5) 4.7–5 (5.3) µm, avl × avw = 9.1 × 5.1 μm; Q av = 1.4, lacrymoid to subcylindrical, rarely slightly curved, thick-walled, smooth, apiculate, hyaline in 5% KOH, non-dextrinoid, congophilous, guttulate. Basidia (20.3) 20.8–24.6 (26.2) × (4.6) 5.2–8 (8.2) µm, avl × avw = 23.2 × 7 μm, narrowly clavate to clavate, two-spored, thick-walled, hyaline in 5% KOH, congophilous. Basidiols (17) 18.3–23.3 (23.5) × (4.5) 4.9–6.8 (7.4) µm, avl × avw = 20 × 6 μm, numerous, narrowly clavate to clavate, thin-walled, congophilous. Cheilocystidia (13.8) 16.5–21.8 (23.1) × (5.5) 6.3–9.2 (10) µm, avl × avw = 12.2 × 7.6 μm, broom cells of the Siccus-type, mostly clavate to broadly clavate, or cylindrical, thick-walled. Pleurocystidia absent. Pileipellis hymeniderm, inconspicuous or broadly clavate, composed of Siccus-type thick-walled broad broom cells, digitate, (12.7) 14.1–16.6 (16.8) × (5.7) 5.8–8.9 (11.7) µm, avl × avw = 15.1 × 7.7 μm, pileus hyphae with 3.1–5.2 µm in diam., avw = 4.2 µm, smooth, narrow, and long, septate, thick-walled, clamp connections present, hyaline in 5% KO. Pileocystidia absent. Stipitipellis a cutis, made up of long and narrow hyphae 2.3–4.7 μm diam., avw = 3.6 μm, thick-walled, septate, parallel, clamp connections present. Caulocystidia absent. Habitat:—Saprotrophic, growing gregariously or in pairs on decaying twigs of shrubs under mixed angiosperm vegetation dominated by Eucalyptus . Known geographical distribution:—So far, known only from the type locality, Pirowal reserve forest, Khanewal district, Punjab , Pakistan . FIGURE 2. a–f Basidiomata of Marasmius pakistanicus (Holotype; LAH38018); g Habitat; Scale bars a–f = 3 mm. Photos by: Muhammad Asif. FIGURE 3. a–n Microscopic features of Marasmius pakistanicus (Holotype; LAH38018) a–c = Basidia, d = Basidiols, e = Basidiospores, f–i = Cheilocystidia, j–l = Pileipellis Siccus-type broom cells, m = Pileipellis hyphae n = Stipitipellis hyphae. Scale bars: a–l = 5 µm, m–n = 3 µm. Photos by: Muhammad Asif. Additional material examined:— PAKISTAN . Punjab province , Pirowal Reserve Forest , Khanewal district ; 30°34′34″ N , 71°98′48″ E; alt. 136 m elev., on grass twigs, 05 August 2022 , Muhammad Asif , SP-95 , ( LAH38019 ). GenBank accession: ITS = PP051301 ; 28S = PP051305 .