Mycena brunneocystidiata J. W. Guo, Z. W. Liu, Y. P. Ge & Q. Na, 2025

Guo, Jingwen, Liu, Zewei, Zeng, Hui, Ge, Yupeng & Na, Qin, 2025, Three new species of Mycena sect. Calodontes (Mycenaceae, Agaricales) from Northeastern China, MycoKeys 125, pp. 51-79 : 51-79

Mycena brunneocystidiata J. W. Guo, Z. W. Liu, Y. P. Ge & Q. Na sp. nov.

Figs 2 , 3 , 4 , 5

Diagnosis.

Pileus brown. Lamellae densely covered with dark brown dots, margin brown. Cheilocystidia, pleurocystidia, caulocystidia and terminal cells of stipitipellis with brownish contents. Differ from M. lammiensis by wider basidiospores (width> 4 μm) and fusiform caulocystidia.

Holotype.

China • Heilongjiang Province, Mudanjiang City, Mudanfeng National Forest Park , 42°45'74"N, 128°14'41"E, 22 August 2024, Jingwen Guo, Tian Wang, Qin Na, Zengcai Liu, Ruipeng Liu, Pengyu Du, Ying Yu, and Yupeng Ge leg., FFAAS 3400 (collection no. NJ 6538 ) .

Etymology.

Name refers to the cheilocystidia, pleurocystidia, and caulocystidia with brown contents.

Description.

Pileus 10–36 mm in diam., plano-convex, with slightly umbo at center, margin revolute, wavy, cracked at mature; * Drab ( XLVI 17 ′′′′) at center, gradually towards margin to PaMid Vinaceous-Drab ( XLV 5 ′′′′ f), Pale Drab-Gray ( XLVI 17 ′′′′ f) to * Drab-Gray ( XLVI 17 ′′′′ d), margin * Drab ( XLVI 17 ′′′′); striate * Hair Brown ( XLVI 17 ′′′′ i), towards the center up to 1 / 2–2 / 3 diam .. Context White ( LIII), 1.0 mm thick, fragile. Lamellae subdecurrent, 23–27 reaching the stipe, 1–3 tiers of lamellulae, White ( LIII), densely covered with Deep Brownish Drab ( XLV 9 ′′′′ i) dots, irregularly intervenose, stretching downward to 2 / 3–3 / 4 of the width of lamellae, edge entirely Deep Brownish Drab ( XLV 9 ′′′′ i), wavy. Stipe 24–44 × 2–4 mm, central, cylindrical; apex to middle * Smoke Gray ( XLVI 21 ′′′′ d) to Pale Smoke Gray ( XLVI 21 ′′′′ f), base * Ecru-Drab ( XLVI 13 ′′′′ d) to * Drab-Gray ( XLVI 17 ′′′′ d), hollow, fragile, apex with Light Drab ( XLVI 17 ′′′′ b) to * Drab ( XLVI 17 ′′′′) striates, sparse White ( LIII) pubescent at base. Odor and taste not distinctive.

Basidiospores (60 / 3 / 2) (5.4) 5.6– 6.3 – 6.9 (7.1) × (2.6) 2.9– 3.2 – 3.5 (4.0) μm [ Q = (1.72) 1.77–2.16 (2.19), Q m = 1.97 ± 0.09] [ holotype (40 / 2 / 1) 6.0– 6.5 – 6.9 (7.1) × 3.0– 3.2 – 3.5 μm [ Q = (1.83) 1.89–2.15 (2.18), Q m = 2.00 ± 0.08], narrowly ellipsoid to cylindrical, colorless, smooth (1000 ×), thin-walled, amyloid. Basidia clavate, 16–21 × 5–7 μm, hyaline, thin-walled, 4 - spored, sterigmata 2–3 μm in length. Cheilocystidia fusiform with tapered apices, 36–62 × 9–14 μm (Fig. 3 G – J , Fig. 4 D 1 ), acicular to lanceolate, 46–84 × 10–17 μm (Fig. 3 M – P , Fig. 4 D 2 ), with brownish contents, thin-walled, smooth. Pleurocystidia similar to cheilocystidia, 39–72 × 8–15 μm, with brownish contents, thin-walled, smooth. Pileipellis a cutis composed of cylindrical cells, 32–121 × 3–6 μm, smooth, thin-walled; terminal cells cylindrical, apex tapering, 34–87 μm in length, apex 1–3 μm, base 3–7 μm, thin-walled, hyaline. Hypodermium formed by fusiform to subglobose hyphae, 20–72 × 12–39 μm, thin-walled, hyaline. Lamellar trama subregular, dextrinoid. Stipitipellis a cutis composed of cylindrical hyphae, 9–18 μm in diam., smooth, thin-walled; terminal cells fusiform or cylindrical, apex tapering, 31–72 × 4–8 μm, with pale brownish contents, thin-walled, smooth; caulocystidia fusiform, 33–70 × 7–13 μm, with pale brownish contents, thin-walled, smooth. Clamps present in all tissues.

Habit and habitat.

Scattered on the litter layer in Acer mono Maxim. , Larix gmelinii (Ruprecht) Kuzeneva , Pinus koraiensis Siebold et Zuccarini , and Quercus mongolica Fischer ex Ledebour mixed forests during summer and autumn.

Known distribution.

Heilongjiang Province, Jilin Province, China.

Additional material examined.

China • Jilin Province, Yanbian Korean Autonomous Prefecture, Antu County, Erdaobaihe Town, Back Mountain of Changbai Mountain Natural History Museum , 42°46'43"N, 128°14'49"E, 17 August 2021, Zewei Liu, Qin Na, Shixin Wang, and Yupeng Ge leg., FFAAS 3401 (collection no. MY 0611 ) .

Notes.

Mycena brunneocystidiata is considered to be a distinct species of sect. Calodontes subsect. Marginatae J. E. Lange on account of its lamellae margins brown and cheilocystidia, pleurocystidia, and caulocystidia with brown contents ( Maas Geesteranus 1992 a, 1992 b). In the subsection, M. lammiensis and M. pelianthina share the same colored lamellae margins, cheilocystidia, and pleurocystidia with purple-brown contents, but M. lammiensis differs in having larger basidiospores (7.5–9.0 × 4.0–5.0 μm) and cylindrical caulocystidia, while M. pelianthina is identified by purple-brown pileus and lacking caulocystidia ( Harmaja 1985; Robich 2003; Harder et al. 2010; Aronsen and Læssøe 2016). Mycena shengshanensis resembles M. brunneocystidiata in growing on the humus layer of Larix gmelinii and having light purple-brown to brown pileus, but differs in colorless, clavate, and thick-walled cheilocystidia ( Liu et al. 2022).

The main shape of cheilocystidia and pleurocystidia in FFAAS 3401 is fusiform with tapered apices (Fig. 5 A – E, K – O ), but in specimen FFAAS 3400, acicular to lanceolate cheilocystidia and pleurocystidia can be observed occasionally, which are larger than the fusiform ones (Fig. 5 F – J, P – T ).

Figures

Figure 2. Basidiomata of Mycena brunneocystidiata. A – D. Collection FFAAS 3400, holotype; E – I. Collection FFAAS 3401. Scale bars: 20 mm (A – B, E, G – H); 1 mm (C, F); 5 mm (D, I). Photographs (A – I) by Jingwen Guo and Yupeng Ge.

Figure 3. Microscopic features of Mycena brunneocystidiata (FFAAS 3400, holotype). A – E. Basidiospores; F. Basidia; G – J. Fusiform cheilocystidia; K – L. Acicular to lanceolate cheilocystidia; M – P. Fusiform pleurocystidia; Q – R. Acicular to lanceolate pleurocystidia; S. Pileipellis and hypodermium; T. Lamellar trama; U. Stipitipellis and caulocystidia. Scale bars: 5 μm (A – E); 10 μm (F); 25 μm (G – R); 20 μm (S – U). Structures (A – E) were rehydrated in 5 % KOH aqueous solution, (G – R, U) were rehydrated in sterile water and (F, S – T) were stained in 1 % Congo red aqueous solution.

Figure 4. Morphological features of Mycena brunneocystidiata (FFAAS 3400, holotype). A. Basidiomata; B. Basidiospores; C. Basidia; D 1. Fusiform cheilocystidia; D 2. Acicular to lanceolate cheilocystidia; E 1. Fusiform pleurocystidia; E 2. Acicular to lanceolate pleurocystidia; F. Stipitipellis and caulocystidia; G. Pileipellis and hypodermium. Scale bars: 20 mm (A); 5 μm (B); 10 μm (C); 25 μm (D 1 – G). Drawings by Jingwen Guo.

Figure 5. Morphological features of the Cheilocystidia and pleurocystidia of Mycena brunneocystidiata. A – E. Cheilocystidia of FFAAS 3401; F – J. Cheilocystidia of FFAAS 3400, holotype; K – O. Pleurocystidia of FFAAS 3401; P – T. Pleurocystidia of FFAAS 3400, holotype. Scale bars: 25 μm (A – E, K – O); 30 μm (F – J, P – T). Drawings by Jingwen Guo.