Marasmiellus thailandicus W. Lu, N. Suwannar. & J. Kumla 2024, sp. nov.
Creators: name: Lu, Wenhua
name: Nutaratat, Pumin
name: Kumla, Jaturong
name: Tibpromma, Saowaluck
name: Elgorban, Abdallah M.
name: Karunarathna, Samantha C.
name: Suwannarach, Nakarin
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Omphalotaceae
Marasmiellus
Marasmiellus thailandicus

description: Marasmiellus thailandicus W. Lu, N. Suwannar. & J. Kumla sp. nov.
Figs 2 A, B, 3
Type.
Thailand • Chiang Mai Province, Chiang Mai University; 18 ° 48 ' 5 " N, 98 ° 57 ' 23 " E; elevation 337 m; on bark of Lagerstroemia macrocarpa Wall. ex Kurz, 5 August 2023, N. Suwannarach & J. Kumla (CMUB 40052). GenBank accession numbers PP 889929 (nrITS) and PP 890009 (nrLSU).
Etymology.
“ thailandicus ” refers to the country Thailand, where the type species was collected.
Diagnosis.
Differs from M. candidus by the presence of a reddish gray to dull red, dry, radially wrinkled surface, grooved pileus with distant lamellae, and obovate or ellipsoid spores.
Macrostructures.
Basidiomata small-sized, marasmioid. Pileus 6–20 mm diam., hemispherical first, expanding to plano-convex with slightly concave, radially sulcate with age, with involute then deflexed or straight margin, not distinctly hygrophanous, translucently striate up to center, reddish gray (10 B 2) to dull red (10 B 3) all over with grayish red (7 B 3) center, grayish red (7 B 3) margin, surface smooth, dry, and dull. Lamellae distant, broadly adnate to subdecurrent, sometimes anastomosing, white to cream-colored, with a reddish white (7 A 2) edge, particularly in young specimens, I = 2–3, L = 11–14. Stipe 4–8 × 1–2 mm, cylindrical, curved, base often slightly swollen, inconspicuous fibrils or scurfy, creamy-white at apex, slightly reddish white (7 A 2) at the base, dry, pruinose all over, Context thin, fistulose or solid, concolorous with surface. Smell and taste indistinct.
Microstructures.
Basidiospores (– 12) 13–16 (– 17) × 4–5 (– 6) μm (average = 15 × 5 μm), Q = (2.1) 2.5–3.5 (– 3.75), Qm = 3.05 ± 0.38, sub-cylindrical to elongate with apiculus, inamyloid, thin-walled. Basidia 20–45 × 7–11 μm, 4 - spored, clavate, sterigmata up to 5 μm. Cheilocystidia 50–53 × 8–13 μm, clavate. Pleurocystidia absent. Trama hyphae cylindrical, thin-walled, hyaline, inamyloid. Pileipellis, a cutis with transitions to a trichoderm, made up of cylindrical; pigment brown, intracellular and minutely incrusting, hyphal 2–4 μm, negative in Melzer’s reagent. Stipitipellis, a cutis of parallel, somewhat skewed, cylindrical, or clavate-shaped, smooth hyphae, thin-walled, up to 7.5 um wide. Caulocystidia absent. Clamp connection present.
Ecology and distribution.
Caespitose, in small groups growing on the bark of Lagerstroemia macrocarpa. Known only from the type locality in northern Thailand.
Additional material examined.
Thailand, • Chiang Mai Province, Chiang Mai University; 18 ° 48 ' 5 " N, 98 ° 57 ' 23 " E; elevation 337 m; on bark of Lagerstroemia macrocarpa, 24 August 2023, N. Suwannarach & J. Kumla (CMUB 40053). GenBank accession numbers PP 889930 (nrITS) and PP 889930 (nrLSU).
description: Published as part of Lu, Wenhua, Nutaratat, Pumin, Kumla, Jaturong, Tibpromma, Saowaluck, Elgorban, Abdallah M., Karunarathna, Samantha C. & Suwannarach, Nakarin, 2024, Morphological and molecular identification of two new Marasmiellus species (Omphalotaceae, Agaricales) from Thailand, pp. 31-48 in MycoKeys 109 on pages 31-48, DOI: 10.3897/mycokeys.109.129791