Butyriboletus hainanensis N.K. Zeng, Zhi Q. Liang & S. Jiang, 2016

Liang, Zhi-Qun, An, Dong-Yu, Jiang, Shuai, Su, Ming-Shen & Zeng, Nian-Kai, 2016, Butyriboletus hainanensis (Boletaceae, Boletales), a new species from tropical China, Phytotaxa 267 (4), pp. 256-262 : 257-260

Butyriboletus hainanensis N.K. Zeng, Zhi Q. Liang & S. Jiang , sp. nov. ( Figs. 2–3 )

MycoBank: MB 816508

Etymology: “ hainanensis ” refers to Hainan Province, China, holotype locality.

Diagnosis: Characterized by its large, brown pileus with thick context and thin hymenophore, a blue-red-black color change of hymenophore and context, a yellow to brownish red stipe with faint reticulations, smooth basidiospores, and an interwoven trichodermal pileipellis.

Holotype: CHINA. Hainan Province: Qiongzhong Country, Yinggeling Nature Reserve , Yinggezui , elev. 850 m, 26 July 2009, N.K. Zeng 334 ( HKAS 59816 ).

Paratype: CHINA. Hainan Province: Qiongzhong Country, Yinggeling Nature Reserve , Yinggezui , elev. 850 m, 26 July 2009, N.K. Zeng 332 ( HKAS 59814 ) .

Basidiomata medium to very large-sized. Pileus 6–20 cm in diameter, subhemispherical to convex, sometimes applanate; surface dry, finely tomentose, pale brown (5C5–6) to brown (9C5–6); margin decurved; context 1–2.8 cm in thickness in the center of the pileus, white (1D1–2), changing blue quickly, then turning red and finally black when injured. Hymenophore poroid, adnate or slightly depressed around apex of stipe; pores angular, 0.3–0.5 mm in diameter, yellow (2A6–7), changing blue quickly, then turning red and finally black when injured; tubes 0.1–1.5 cm in length, pale yellow (1A5–6), changing blue quickly, then turning red and finally black when injured. Stipe 6–13 × 1.5–3 cm, central, subcylindric, solid; surface dry, grayish white (1B1), with faint reticulations, upper 1/3 yellow (2A6–7), lower 2/3 brownish red (9B5–6); context white (1D1–2), changing blue quickly, then turning red and finally black when injured; annulus absent. Basal mycelium white (1A1). Odor indistinct.

Basidia 29–34 × 7–10 μm clavate, thin-walled, four-spored; sterigmata 5–6 μm long. Basidiospores [66/3/2] 7.5–10(–11) × 4–5 μm, Q = (1.70–)1.80–2.25(–2.50), Q m = 2.06 ± 0.16, subfusiform to ellipsoid, slightly thick-walled (up to 0.5 μm), olive brown to yellowish brown in KOH, smooth. Hymenophoral trama boletoid. Cheilocystidia 23–51 × 5–12 μm, abundant, subfusiform or fusiform, thin-walled, sometimes with yellowish brown contents, without encrustations. Pleurocystidia 38–69 × 8–14 μm, abundant, fusiform or subfusiform, thin-walled, sometimes with brown or golden brown contents, without encrustations. Pileipellis an interwoven trichoderm 100–150 μm thick, composed of colorless, pale yellowish brown to yellowish brown in KOH, thin- to slightly thick-walled (up to 0.5 μm) hyphae 3–9 μm diam; terminal cells 16–63 × 4–9 μm, narrowly clavate or subcylindrical, with obtuse apex. Pileus trama composed of thin- to slightly thick-walled (up to 0.5 μm) hyphae 3–8 μm diam. Stipitipellis an interwoven trichodermlike structure 100–150 μm thick, composed of thin- to slightly thick-walled (up to 1 μm) hyphae with narrowly or broadly clavate, subfusiform or fusiform terminal cells (15–65 × 6–13 μm), and some emergent hyphae with clavate or subcylindrical terminal cells. Stipe trama composed of cylindrical, thin to slightly thick-walled (up to 1 μm), parallel hyphae 4–13 μm diam. Clamp connections absent in all tissues.

Habitat: Scattered to gregarious on the ground in broadleaf forests dominated by Fagaceae .

Known distribution: Southern China.

Additional materials examined: CHINA. Hainan Province: Qiongzhong Country, Yinggeling Nature Reserve , Yinggezui , elev. 850 m, 26 July 2009, N.K.Zeng 333 ( HKAS 59815 ) ; same location, 16 June 2013, N.K.Zeng 1197 ( FHMU) ; Baisha Country, Yinggeling Nature Reserve , Nankai , elev. 380 m, 31 July 2015, N.K.Zeng 2418 ( FHMU) .

Figures

FIGURE 2. Basidiomata of Butyriboletus hainanensis. [a from N.K.Zeng 2418 (FHMU); b from N.K.Zeng 1197 (FHMU); c from HKAS 59816, holotype; d–e from HKAS 59815; f from HKAS 59814, paratype]. Photos by N.K. Zeng.

FIGURE 3. Microscopic features of Butyriboletus hainanensis (HKAS 59816, holotype). a. Basidia and pleurocystidia. b. Basidiospores. c. Cheilocystidia. d. Pileipellis. e. Stipitipellis. Bars = 10 μm. Drawings by N.K. Zeng.