Boletellus brunoflavus Z.J. Lin, X.X. Huang, Y.S. Liang & L.H. Qiu, 2022

Lin, Zhi-Jun, Huang, Xiao-Xia, Liang, Ying-Shan & Qiu, Li-Hong, 2022, Boletellus brunoflavus sp. nov. (Boletaceae, Basidiomycota) from Baiyun Mountain, Guangzhou, China, Phytotaxa 567 (3), pp. 245-256 : 251

Boletellus brunoflavus Z.J. Lin, X.X. Huang, Y.S. Liang & L.H. Qiu , sp. nov. ( Figs. 2 , 3 )

MycoBank: MB 843835

Etymology:—The epithet “ brunoflavus ” refers to its brownish yellow pileus.

Holotype:— CHINA. Guangdong Province: Guangzhou City, Baiyun District, Baiyun Mountain , 23°10′44″N 113°17′34″E, alt. 293 m, 23 August 2021 ( GDGM 87996 ).

Diagnosis:—This species differs from other species in Boletellus by the combination of the characteristics viz. small to medium size basidiomata, yellowish brown pileus with reddish brown tints, relatively small basidiospores with longitudinal striae only, golden to brownish yellow hymenophore, pale yellow context that turns blue or greenish blue when injured, and stipe with upper 1/4 to 1/5 part concolorous with hymenophore.

Description:— Basidiomata small to medium size. Pileus 14–55 mm in diam., convex when young, plain to uplifted at maturity; surface dry, sparse tomentose, light brown (#DBBD75) to brown (#724226) with some reddish brown (#B48277) tints depending on ages. Context pale yellow (#CEBB6E), turning blue (#19334D), cyanescent (#4A7B8E) or greenish blue (#354517) immediately when bruised. Stipe 23–29 mm in length, 3–10 mm in width, central, solid, subclavate to clavate-bulbous; surface dry, without reticulation, the upper 1/5 to 1/4 section golden (#FFD501) to brownish yellow (#BB793A) with age which is concolorous with hymenophore, and chocolate brown (#57290B) with garnet (#BB6553) tints below, basal mycelium white; context turning greenish grey (#505647) immediately when bruised. Hymenophore poroid, adnate to stipe; golden (#FFD501) at maturity, brownish yellow (#BB793A) when old. Tubes 2–5 mm in length, depressed around stipe, pale yellow (#F9F68F) when young, golden (#D79749) at maturity, and brown (#4B240A) to olivaceous brown (#121111) when old. Pores angular, nearly oval around stipe, mostly round, relatively smaller near pileus margin, concolorous with tubes at young, yellowish-brown (#F2A775) to dark grey (#433D3D) when old. Odor not distinctive.

Basidiospores [61/10/7] (6.1–)6.4–8.2(–8.9) × (2.0–)2.3–3.3(–3.6) μm, Q = (2.1–)2.2–3.2(–3.9), Q m = 2.6 ± 0.3, broadly ellipsoid to sub-fusiform, inamyloid, with longitudinal striae only; golden yellow or yellow in KOH solution; thin-walled. Basidia 22.6–35.6 × 6.2–10.3 μm, thin-walled, clavate, hyaline in KOH solution; 4-sterigmata (sometimes 2 or 3-sterigmate), sterigmata 1.4–3.5 μm in length. Basidioles 25.6–31.0 × 6.3–9.6 μm, cylindrical, clavate or broadly clavate. Pleurocystidia 27.9–52.2 × 5.0–5.8 μm, not abundant, clavate to fusiform, thin walled, hyaline in KOH solution. Pileipellis trichodermal, hyphae 3.0–5.1 μm in diam., hyaline or yellowish-brown contents in KOH solution; end cells hyaline in KOH solution, cylindrical to fusiform. Stipitipellis a trichoderm-like structure, hyphae 3.3–6.6 μm in diam., thin-walled, parallel, some tangles, hyaline or pale yellow in KOH solution and hyaline or yellowish brown in Melzer’s reagent. Clamp connections absent.

Habitat:—Solitary or gregarious on soil in subtropical forests.

Distribution:—Currently known from Guangdong Province, China.

Additional specimens examined:— China. Guangdong Province: Guangzhou, Baiyun Mountain , 12 June 2021 ( GDGM 87993 , GDGM 87994 , GDGM 87995 , B21061253), 3 July 2021 (B21070323), 17 July 2021 (B21071718), 16 August 2021 (B21081640), 4 September 2021 (B21090416) .

Figures

FIGURE 2. Boletellus brunoflavus sp. nov.: a–d. Basidiomata (a: GDGM 87996, holotype; b: B21061253; c: B21081640; d: B21090416); e. Scanning electron micrograph of basidiospores (GDGM 87996, holotype). Photos by L.H. Qiu and Z.J. Lin. Scale bar:A: a–d = 10 mm; e = 1 μm.

FIGURE 3. Microscopic features of Boletellus brunoflavus sp. nov.: a. Basidiospores; b. Basidia; c. Pleurocystidia; d. End-cells of pilleipellis; e. Stipipellis. Scale bar: a–d = 10 μm. Drawings by Z.J. Lin.