taxonID	type	description	language	source
03AB87853C139A099BA6FB43E7CF7F2A.taxon	diagnosis	Diagnosis: — Distinguishable from the close relative L. cladopus by its smaller basidiospores and longer basidia. Etymology: — ‘ saisamorniae ’ refers to Emeritus Prof. Dr. Saisamorn Lumyong in honor of her 75 th birthday and over 35 years of contribution to Thai mycology. Holotype: — THAILAND. Chiang Mai Province, Mueang Chiang Mai District, Chiang Mai University, 18 ° 48 ’ 13 ” N 98 ° 57 ’ 21 ” E, elevation 334 m, on decaying wood in a tropical deciduous forest, 8 August 2019, J. Kumla & N. Suwannarach, CMUB 40076. Gene sequences (from holotype): — PV 244426 (ITS), PV 241809 (nrLSU), and PV 252128 (rpb 1) Description: — Basidiomata small to medium-sized. Pileus 10 – 85 mm in diameter, convex to applanate, deeply depressed at center or infundibuliform shaped, with concentrically fibrillose squamules crowded at center toward margin, white (4 A 1) to yellowish-white (3 A 2 – 4 A 2), margin smooth or broken when mature, with white fibrillose. Lamellae decurrent, white (4 A 1), narrowed, up to 2 mm wide, with white (4 A 1) smooth margin. Stipe central to lateral, 20 – 90 × 2.5 – 10 mm, cylindrical, equal or slightly tapering to base, white (3 A 1) to yellowish-white (3 A 2), smooth or with white (3 A 1) to yellowish-white (3 A 2 – 4 A 2) fibrillose. Annulus absent. Context white (4 A 1) at pileus and stipe, fleshy-tough to leathery, consisting of a dimitic hyphal system with generative and skeletal hyphae. Generative hyphae 2.0 – 5.5 μm in diameter, hyaline, thin-walled, frequently branching, with clamp connections. Skeletal hyphae 2.5 – 10.0 μm wide, hyaline, thick-walled, unbranched or with an occasional lateral branched. Spore print white. Basidiospores [150 / 10 / 4] (4.5) 5.1 – 5.6 (6.5) × (3.0) 3.2 – 3.8 (4.0) μm, Q = 1.38 – 1.83, Q m = 1.60 ± 0.12, broadly ellipsoid to ellipsoid, occasionally elongate, thin-walled, smooth, hyaline, inamyloid. Basidia 18.0 – 27.5 × 4.5 – 7.0 μm, clavate, thin – walled, hyaline, 4 - spored, sterigmata up to 5.0 μm long. Pleurocystidia absent. Hyphal pegs abundant, extending up to 50 μm in diameter, consisting of thin-walled, cylindric hyphae, hyaline, 1.0 – 3.0 μm in diameter. Cheilocystidia 15.0 – 45.0 × 3.0 – 6.0 μm, narrowly clavate to clavate or narrowly cylindrical to cylindrical, hyaline, thin-walled. Hymenophoral trama hyaline, irregular and intermixed, similar to the context. Pileipellis cutis, trichoderm, cylindric, terminal elements with obtuse apices, sometimes with a narrowed or slightly strangulated apex, up to 50 μm long, a dimitic hyphal system; generative hyphae 2.0 – 4.5 μm in diameter, hyaline, thin-walled, branched, with clamp connections; skeletal hyphae 2.5 – 10.0 μm in diameter, hyaline, unbranched or with an occasional lateral branched, thick-walled. Stipitipellis cutis, similar to the pileipellis in composition but the terminal elements often tend to form small, loose aggregations. Clamp connections abundant at all tissues. Ecology and distribution: — Fruiting solitary or gregarious on decaying wood and soil in a tropical deciduous forest. Known only from the type locality in northern Thailand. Additional specimens examined: — THAILAND, Chiang Mai Province, Mueang Chiang Mai District, Chiang Mai University, 18 ° 48 ’ 13 ” N 98 ° 57 ’ 21 ” E, elevation 334 m, on soil in a tropical deciduous forest, 3 July 2020, J. Kumla & N. Suwannarach, SDBR-CMUNK 0795, 18 ° 48 ’ 20 ” N 98 ° 57 ’ 25 ” E, elevation 335 m, on decaying wood in a tropical deciduous forest, 17 July 2021, J. Kumla & N. Suwannarach, SDBR-CMUNK 1515; Doi Saket District, 18 ° 53 ’ 2 ” N 99 ° 9 ’ 17 ” E, elevation 343 m, local market, 26 July 2021, Kumla J. and Suwannarach N., SDBR-CMUNK 0837. Note: — Morphologically, L. saisamorniae resembles L. cladopus, L. concavus (Berk.) Corner, and L. squarrosulus in terms of pileus color. However, the larger basidiospores (6.5 – 8.5 × 3.7 – 4.7 μm) and shorter basidia (15.0 – 17.5 × 4.0 – 4.5 μm) in L. cladopus distinguish it from L. saisamorniae (Berkeley 1852, Singer 1956, Pegler 1977). Notably, the presence of the longer basidiospores in L. concavus (5.5 – 8.0 × 2.0 – 4.0 μm) clearly differs it from L. saisamorniae, and L. concavus is only found in South America (Berkeley 1852; Singer 1956, Pegler 1977, 1983, Minter et al. 2001, Franco-Molano et al. 2005, Vasco-Palacios et al. 2005, Bononi et al. 2008, Gates et al. 2021, Angelini 2022). The longer and narrower size of basidiospores (5.0 – 8.0 × 1.5 – 3.0 μm) in L. squarrosulus make it different from L. saisamorniae (Corner 1981, Pegler 1977, 1986, Sysouphanthong et al. 2023). Phylogenetically, L. saisamorniae formed a monophyletic clade sister to L. cladopus. The ITS sequences of L. saisamorniae showed similarity values ranging from 79.90 % to 80.20 % when compared to the ITS sequences of L. cladopus VKMK 05 and S 3004. Moreover, a pairwise nucleotide comparison of ITS data indicated that L. saisamorniae differed from L. cladopus VKMK 05 and S 3004 by 20.75 % (137 / 660 bp including gap) and 21.06 % (139 / 600 bp including gap), respectively.	en	Kumla, Jaturong, Kaewnunta, Atsadawut, Suwannarach, Nakarin (2025): Lentinus saisamorniae (Polyporaceae, Polyporales), a new edible macrofungus from northern Thailand. Phytotaxa 705 (2): 149-161, DOI: 10.11646/phytotaxa.705.2.2, URL: https://doi.org/10.11646/phytotaxa.705.2.2
