Marasmius qujingensis W.H. Lu., Karun. & Tibpromma, sp. nov.

Index Fungorum number: IF 900394; Mycobank number: MB 900394; Facesoffungi number: FOF 14111; Fig. 1

Etymology – “qujingensis” refers to Qujing City where the species was first collected.

Holotype – HKAS 127151.

Pileus 9 to 30 mm in diam., hemispherical, convex with dark brown conical papilla at the center when young, expanding to broadly convex with age; smooth and entire, moisture-laden, glabrous; lead grey (2B2) at dark disc spot (2F2) when young, dull yellow and yellowish grey (3B2–3) at the disc with age. Lamellae adnate to shallowly adnate, medium spaced to rather distant, yellowish white (1A2) with a white edge. Stipe 25–70×5 mm, cylindrical, central, glabrous, waterlogged, moist, white, light orange (5A4) with age, hollow, some stipes arising directly from pale orange rhizomorphs. Basidiospores 5.5–10 × 3–3.5 μm (n=25), thin-walled, smooth, hyaline, pyriform, ellipsoid. Basidia (16)21–35×4–6 μm, clavate, inamyloid, thin-walled, with 4 sterigmata. Cheilocystidia of Siccus-type broom cells; main body 8–12×6–8 μm, clavate to pyriform, hyaline, inamyloid, thin-walled. Pileipellis hymeniform, mottled, with Siccus-type broom cells, clavate to pyriform or turbinate, hyaline, inamyloid, and thin-walled. Pileus trama inamyloid, interwoven. Lamellar trama hyphae interwoven, cylindrical, smooth, hyaline, inamyloid, thin-walled, non-gelatinous. Clamp connections present.

Material examined – China, Yunnan Province, Qujing Normal University, 25° 31′ 16′′ N 103° 45′ 12′′ E, elev. 1628 m, 14 June 2022, QJ130, W. Lu & S. Karunarathna.

Additional specimens examined – China, Yunnan Province, Qujing Normal University, 25° 31′ 16′′ N 103° 45′ 12′′ E, elev. 1628 m, 14 June 2022, HKAS 128153(QJ309), W. Lu & S. Karunarathna.

GenBank numbers – ITS: OQ755409 (HKAS 127151), OQ755410 (HKAS 128153(QJ309).

Notes – Marasmius qujingensis is morphologically similar to M. torquescens and M. wynneae. However, M. qujingensis differs from M. wynneae by having beige gray, dry, wavy, and depressed at the center of the cap, and stipe, black at the base (Berkeley & Broome 1859). Marasmius qujingensis differs from M. torquescens by having light brown, yellowish-brown, reddish-brown, and dark brown in between, ridged to wrinkled edge pileus; pileipellis composed of mixed siccus-type broom cells and non-setulose cells (Quél 1872). In our phylogenetic study (Fig. 2), M. qujingensis formed a separate branch from all other known Marasmius species with relatively good statistical support (100% ML/1.00 PP). In addition, M. qujingensis differs from M. coarctatus and M. trinitatis in the comparison of ITS gene fragments (M. coarctatus: 40/627, 6.37%; M. trinitatis: 74/627, 11.8%, without gaps). Therefore, M. qujingensis is introduced as a distinct new species based on morphological and molecular evidence.

Figure 1 – Marasmius qujingensis (HKAS 127151, holotype). a Basidiomata. b Basidia. c Basidia and Basidioles. d Basidioles e Cheilocystidia. f Clamp connection. g Caulocystidia. h, i Basidiospores. Bars: a=1 cm. b, c, d, g=10 μm. e, f=20 μm. h, i=5 μm

Figure 2 – Phylogram generated from maximum likelihood analysis based on ITS sequences data. Related sequences were obtained from Bhunjun et al. (2022), Oliveira (2020), and Zhang et al. (2023d). Eighty-seven strains are included in the sequence analysis, which comprises 627 characters with gaps. Marasmius yunnanensis (Dai 19782) and M. yunnanensis (Dai 19857) were used as theoutgroup taxa. The tree topology of the ML analysis was similar to the BYPP. The best-scoring RAxML tree with a final likelihood value of −6270.324271 is presented. The matrix had 364 distinct alignmentpatterns, with 3.67% of  undetermined characters or gaps. Estimated base frequencies were as follows; A=0.247688, C=0.198222, G=0.217049, T=0.337041; substitution rates AC=0.884748, AG=3.076732, AT=0.975543, CG=0.390992, CT=3.644064, GT=1.000000; gamma distribution shape parameter α=0.727557. Bootstrap support values for ML equal to or greater than 65% and BYPP equal to or greater than 0.90 are given above the nodes. Newly generated sequences are in bold and blue