Marasmius subpurpureostriatus J. Q. Yan & H. Chen 2025, sp. nov.

Marasmius subpurpureostriatus J. Q. Yan & H. Chen sp. nov. Fig. 5 Etymology. “subpurpureostriatus” refers to its macroscopic morphology, which is similar to that of Marasmius purpureostriatus. Holotype. China • JiangXi Province, Nanchang Botanical Garden, 26 April 2023, collected by Xiao-Lin Yuan, HFJAU 4740. Diagnosis. Marasmius subpurpureostriatus is mainly characterized by the rather small basidiomata, grayish-green pileus with deep violet sulcate; the stipe surface is densely pruinose; basidiospores clavate to fusoid-clavate, 17.5–22.0 × 4.0–5.5 μm; pleurocystidia absent; cheilocystidia clavate to broadly clavate, occasionally appearing subfusiform, apex obtuse, rarely with short papilla. It differs from M. purpureostriatus by having smaller spores, which are shorter than 22 μm. Description. Pileus 20–32 mm, plano-convex to plane, with obtuse umbo at center, smooth, with dark sulcate up to center from the margin, grayish-green (28 B 4), light green (28 A 4–5) sulcate dark violet (18 F 4). Context thin. Lamellae 1.0– 2.5 mm broad, adnexed, ventricose, distant, with 0–1 tier of lamellulae, yellowish gray (4 B 2) with white, edges even, concolorous. Stipe 53–70 mm long, 1.5–3.0 mm thick, central, cylindrical with a subbulbous base, pruinose, hollow, apex dark violet (15 F 5), gradually paler toward the base, base reddish brown (8 E 4). The base covered by white mycelium. Basidiospores (16.5) 17.5–22.0 (23.5) × 4.0–5.5 (6.0) μm (av = 20.0 × 5.0 μm), Q = (3.0) 3.5–4.5 (5.0), clavate to fusoid-clavate, often curved in profile, 4.0–6.5 μm broad, clavate in face view, smooth, colorless, hyaline, inamyloid, thin-walled. Basidia 40.0–50.0 × 8.0–14.0 μm, clavate, 4 - spored. Pleurocystidia absent. Cheilocystidia 13.0–31.0 × 6.0–13.0 μm, irregularly clavate to broadly clavate, rarely subfusiform, apex obtuse, rarely with short papilla, smooth, thin-walled. Pileipellis a hymeniderm composed of cells 16.5–34.0 × 9.0–16.0 μm, pyriform or broadly clavate, smooth, hyaline, thin-walled. Lamellae trama interwoven, with hyphae 4.0–10.0 μm in diam, hyaline, dextrinoid, thin-walled, non-gelatinous. Stipitipellis a cutis composed of cylindrical hyphae 4.0–7.5 μm wide, parallel, smooth. Caulocystidia absent. Clamp connections present. Habitat. Scattered on soil in broad-leaved forest. Note. Based on molecular and morphological evidence, M. subpurpureostriatus belongs to subg. Globulares ser. Purpureostriati (Oliveira et al. 2020 b; Oliveira et al. 2024). Within this series, M. subpurpureostriatus is morphologically similar to M. purpureostriatus, M. pseudopurpureostriatus Wannathes, Desjardin & Lumyong, and M. albopurpureus T. H. Li & C. Q. Wang. However, M. purpureostriatus is distinguished by a long and narrow stipe (52–103 × 0.5–1.5 mm), larger basidiospores (up to 28 μm long), and cheilocystidia that are exclusively cylindrical, broadly clavate, or pyriform (Desjardin and Horak 1997; Wannathes et al. 2009 a). M. pseudopurpureostriatus has a glabrous stipe surface, larger basidiospores (up to 25.0 μm long), and cheilocystidia restricted to clavate or broadly clavate forms (Wannathes et al. 2009 a); M. albopurpureus is distinguished by a strongly rugulose to sulcate pileus (white to purple), cream to purple lamellae, and cheilocystidia that are solely clavate to broadly clavate (Wang et al. 2015). In addition, morphologically, only M. bekolacongoli Beeli and M. violaceoides Antonín share similar morphological characteristics with the new species M. subpurpureostriatus, including a hymenidermal pileipellis composed of Globulares - type cells, the basidiospores measuring 16.0–24.0 μm in length, and absence of pleurocystidia. However, M. bekolacongoli has a larger pileus (30–67 mm) with a yellow colored or tinged striae, and a much longer stipe (50–150 mm) with pale yellow and light brown downward color (Beeli 1928; Douanla-Meli and Langer 2008; Antonín et al. 2010 a); M. violaceoides exhibits a distinctly campanulate, violaceous pileus, a very long and glabrous stipe (110–125 mm) (Antonín 2004).