Marasmiellus scandens (Massee) Dennis & D. A. Reid

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, MycoKeys 109, pp. 31-48 : 31-48

Marasmiellus scandens (Massee) Dennis & D. A. Reid , Kew Bull. [11] (2): 289 (1957)

Figs 2 D , 5

Macrostructures.

Basidiomata small-sized, marasmioid. Pileus 5–10 mm diam., orbicular when young and then convex at age, streaked from disc to margin, margin entire, wavy to irregular, decurved or greatly reflexed, surface dry, smooth, white pruinose, white to grayish orange (5 B 4–5), grayish orange (5 B 4) at the margin. Lamellae adnate, subdistant, with 2–3 series of lamellulae, 14–16 major lamellae, unequal, narrow, pale white at face and edge. Smell and taste none. Stipe 4–6 × 1–2 mm, often curved, lateral or central, disc at the base, dry, surface smooth, whitish to pale orange (5 A 3); Context thick, fistulose, orange white (5 A 2–3).

Microstructures.

Basidiospores 7–9 (– 10) × (3) 3.5–4.5 (– 6) µm (average = 8 × 4.5 μm), Q = 1.4–1.8 (– 2), Qm = 1.74 ± 0.11, broadly ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia 10–12.5 × 3–4.5 µm, clavate, 4 - spored, sterigmata up to 1.5 µm. Cheilocystidia abundant, 15–17 (– 22) × 8–9 (– 11) µm, broom-cell type with finger-like excrescences in the upper half, hyaline, thin-walled. Pleurocystidia absent. Pileipellis with poorly Ramealis - structure, trama hyphae 4–9 µm, negative in Melzer’s reagent. Stipitipellis hyphae up to 5 μm wide, smooth, thin-walled, trama not observed, negative in Melzer’s reagent. Clamp connections present.

Ecology and distribution.

Caespitose, in small groups on decaying leaf of Metroxylon sagu in southern Thailand (This study), on Aquilaria sinensis (agarwood) trees in China ( Zhang et al. 2023), and on the stem of mangosteen in Malaysia ( Turner 1971), on cocoa in Australia, Ghana, Caribbean, Papua New Guinea, and Solomon Islands ( Amoako-Attah et al. 2020; Ali et al. 2021), on coffee in Fiji, Guinea, and Sierra Leone ( Lu et al. 2022).

Material examined.

Thailand • Phatthalung Province, Khuan Khanun, Sago Palm ( Metroxylon sagu ) Forest , 7 ° 44 ' 02 " N, 99 ° 59 ' 47 " E; elevation 24 m; on decaying leaf of Metroxylon sagu ; 3 September 2023; P. Nutaratat, N. Suwannarach & J. Kumla, ( CMUB 40056 ). GenBank accession numbers PP 889933 (nrITS) and PP 890013 (nrLSU) .

Figures

Figure 2. Habitat of Marasmiellus species in the present study A, B Marasmiellus thailandicus (CMUB 40052, holotype) C Marasmiellus minutisporus (CMUB 40054, holotype) D Marasmiellus scandens (CMUB 40056, new record). Scale bars: 10 mm (A – D).

Figure 5. Marasmiellus scandens (CMUB 40056, new record) A basidiospores B basidia C cheilocystidia D terminal elements of pileipellis. Scale bars: 5 µm (A – C); 10 µm (D).