Collybiopsis menehune (Desjardin, Halling & Hemmes) R.H. Petersen,

Mycotaxon 136(2): 343 (2021) FIGURE 6 Index Fungorum number: IF556192

Pileus 22–30 mm, plano-convex to slightly concave, glabrous, margin translucent-striate to striate, greyish orange to brown (5–7B–E5–7) at center, and light orange to orange white (5A2–7) towards margin. Lamellar adnate, close (48– 52) with 1–2 series of lamellulae, white to orange white (5A2), narrow (2 mm). Stipe 40–47 × 1.5–2.0 mm, central, cylindrical, pubescent, insititious, brownish orange (5C4) at apex, yellowish brown (5E8) at base; context thin. Odor and taste are not distinctive.

Basidiospore [75/3/3] 6–8 × 3–4 µm [x̄ = 7.41 ± 0.45 × 3.46 ± 0.27 µm, Q = 1.75–2.66, Q m = 2.17 ± 0.19] elongate-ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia 21–24 × 5–7 µm, clavate, with 4 sterigmata, thin-walled. Cheilocystidia scattered, 20–37.5 × 5–10 µm, subcylindrical, clavate, irregular in shape, lobed broad knob-like outgrowths, sometimes 2-celled, hyaline, inamyloid, thin-walled. Pleurocystidia absent. Lamellar trama regular, 3–6 µm, cylindrical, smooth, hyaline to pale yellow, inamyloid, thin-walled. Pileipellis cutis of radially arranged hyphae, 3–5 µm, cylindrical, pale yellow, inamyloid, diverticulate terminal cells, incrusted. Pileocystidia absent. Pileus trama subregular to interwoven, 4–8 µm, cylindrical, smooth, hyaline to pale yellow, inamyloid, thin-walled. Stipitipellis cutis, 2–4 µm, cylindrical, hyaline to pale yellow, smooth, inamyloid, some hyphae incrusted. Stipe trama cutis, 3–5 µm, cylindrical, smooth, pale yellow, inamyloid. Caulocystidia abundant, 47–80 × 4–7 µm, cylindrical, irregular in shape, flexuose, sometime 2 celled, hyaline, inamyloid, thin walled. Clamp connections are present in all tissues.

Habitat and known distribution:—Fruiting scattered to gregarious on soil. Known from USA (Hawaii) (Desjardin et al. 1999), India (Dutta et al. 2015), Indonesia (Wilson et al. 2004), Korea (Kim et al. 2022), Pakistan (Saba & Khalid 2014), and Thailand (This study).

Material examined:— THAILAND, Sukhothai Province, Sri Satchanalai National Park 99°48´44´´N 17°55´12´´E, elevation 227 m, on rotten wood, 15 June 2019, N. Wannathes, J. Kumla, N. Suwannarach, and S. Khuna, BKF10267 ; Chiang Mai Province, Chiang Mai University, 18°48´7´´N 98°57´23´´E, elevation 330 m, leaf litter, 10 August 2022, W. Phonrob, SDBR-CMUWP124 ; Phatthalung Province, Khuan Khanun, sago palm ( Metroxylon sagu) forest, 7°43´56´´N 99°59´48´´E, elevation 22.2 m, decaying wood and twigs, 23 October 2022, P. Nutaratat, J. Kumla, and N. Suwannarach, SDBR-TSU012 ; Thaksin University, Phatthalung campus, 7°48´36´´N 99°56´49´´E, elevation 20.4 m, on soil, 24 October 2022, P. Nutaratat, J. Kumla, and N. Suwannarach, SDBR-TSU044 .

Note:—Thai materials have macroscopic and microscopic features that agree well with the descriptions of Dutta et al. (2015) and Saba & Khalid (2014). Thai materials were nested in C. menehune clade (FIGURES 2 and 3). Morphologically, C. menehune is similar to C. indocta and C. subcyathiformis; however, C. subcyathiformis differs from C. menehune by having a longer stipe (20–125 × 1–5 mm), smaller basidiospores (4.5–7.8 × 2.3–3 μm), and a filiform cheilocystidia (Pegler 1977). The different characteristics of the microscopic features of C. indocta and C. menehune are mentioned above. Phylogenetically, C. menehune is distinct from C. indocta and C. subcyathiformis (FIGURES 2 and 3).