Strobilomyces minor L.H. Han & K. Zhao, 2019

Han, Li-Hong, Zhao, Kuan, Liu, Chao, Chu, Hong-Long & Tang, Li-Zhou, 2019, Strobilomyces minor (Boletaceae), a new species associated with fagaceous plants in Central China, Phytotaxa 397 (1), pp. 55-64 : 60-62

Strobilomyces minor L.H. Han & K. Zhao , sp. nov. Figs. 2a–2b , 3 , 4

MycoBank: — MB 828626 Etymology: — “ minor ” refers to the small size of basidiomes. Holotype: — CHINA. Hunan Province: Hengyang City, Hengshan County, Hengshan Mountain , on the ground in a mixed forest of

Cyclobalanopsis sessilifolia (Blume) Schott. and Lithocarpus mairei (Schottky) Rehd. , elev. 628 m, 14 August 2018, L.H. Han 1713

(HKAS 101909!).

Description: —Pileus 15–40 mm in diameter, at first convex then applanate; surface dry, light khaki (5A2) to dirty white (5A1), covered with light yellowish brown (6A2), appressed scales, 1–3 mm high, 3–6 mm in diameter at base; margin appendiculate with more or less obtriangular veil remnants concolorous with pileal surface; context white (8A1), staining grayish black to light rusty red (6B2) then black (10E1) when bruised. Hymenophore adnate, with decurrent tooth; surface dirty white (6A1) when young, smoky gray (8C1) when mature; pores angular, large, 1–2 mm in diameter; tubes up to 7–10 mm long; pores and tubes concolorous, whitish (14A1) then fuliginous (4B1), immediately staining rusty red (6C8) and then black (16F8) on exposure. Stipe 30–80 mm long, 3–5 mm in diameter, subcylindrical, surface reticulate with shallow and elongate meshes above, covered with thick tomentose light yellowish brown (6A2) scales below; stipe context white (8A1), becoming more or less a light rusty red (6B2) above and dark red (76E) below; annulus absent; basal mycelium dirty white (5B1) to grayish white (6B1).

Basidiospores [80/4/2] 8–9.5(10) × (6.5)7–8.5(9) μm (Q = 1.06–1.23(1.29), Q m = 1.14 ± 0.06) excluding ornamentation, subglobose to broadly ellipsoid, dark brown (7D4) in 5% KOH solution, reticulate with meshes 2–3.5 μm in diameter and 1–2 μm high; apiculus 0.5–1 μm long, with a smooth adaxial patch. Basidia 25–47 × 12–19 μm, clavate, four-spored; sterigmata 4–6 μm long. Hymenophoral trama boletoid; hyphae cylindrical, 6–10 μm in diameter. Cheilocystidia 30–36 × 14–20 μm, numerous, fusiform to narrowly clavate, hyaline or with brownish (5D6) plasmatic pigment, thin-walled. Pleurocystidia 35–67 × 13–23 μm, narrowly clavate to oblong, thin-walled. Pileipellis squamules on the pileal surface an intricate trichodermium, composed of 8–14 μm wide cylindric hyphae with short obtuse terminal cells; cell wall dark brownish (5D6), slightly thickened (<1 μm). Pileal trama composed of 7–10 μm wide interwoven hyphae. Stipitipellis a trichoderm with hyphae of scales on stipe similar to those on pileus. Stipe trama composed of 5–9 μm wide, vertically to subvertically arranged, cylindrical hyphae. Clamp connections not seen in any tissue.

Habitat and distribution: — Solitary in a mixed forest of Cyclobalanopsis sessilifolia and Lithocarpus mairei ; currently only known from the type locality.

Additional specimens examined:— CHINA. Hunan Province: Hengyang City, Hengshan County, Hengshan Mountain, on the ground in a mixed forest of Cyclobalanopsis sessilifolia and Lithocarpus mairei , elev. 650 m, 14 August 2018, L.H. Han 1714 (HKAS 101910).

Figures

FIGURE 2. Basidiomes of Strobilomyces minor. a. Basidiomes (HKAS 101909, holotype). b. Grayish black to light rusty red color change when cut (image taken immediately after sectioning) (HKAS 101909, holotype). Bars = 1 cm. Photos by Li-Hong Han.

FIGURE 3. Microscopic characters of Strobilomyces minor (HKAS 101909, holotype). a. Basidia and pleurocystidium; b. Cheilocystidia; c. Pileipellis. Bars = 10 μm. Drawings by Li-Hong Han.

FIGURE 4. SEM of basidiospores of Strobilomyces minor from dried specimen (HKAS 101909, holotype). Photos by Jian-Wei Liu.