Aureoboletus longicollis (Ces.) N.K. Zeng & Ming Zhang, 2015

Zeng, Nian-Kai, Zhang, Ming & Liang, Zhi-Qun, 2015, A new species and a new combination in the genus Aureoboletus (Boletales, Boletaceae) from southern China, Phytotaxa 222 (2), pp. 129-137 : 133-135

Aureoboletus longicollis (Ces.) N.K. Zeng & Ming Zhang , comb. nov. ( Figs. 2e–i , 4 and 5 )

Mycobank: MB 812120

Basionym: Boletellus longicollis (Ces.) Pegler & T.W.K. Young, Transactions of the British Mycological Society 76(1): 115, 1981 Boletus longicollis Ces., Atti dell´Accademia di Scienze Fisiche e Matematiche Napoli 8(8): 4, 1879

Basidiomata medium-sized. Pileus 5–6 cm in diameter, conical, umbonate when young, then convex to applanate; surface strongly viscid, sometimes rugose, covered with pale brown, brown, reddish brown to dark red squamules; margin slightly projecting; context 0.3–1.1 cm in thickness in the center of the pileus, yellowish white, unchanging in colour when injured. Hymenophore poroid, depressed around apex of stipe; pores angular, 0.1–0.2 cm in diameter, yellow to pale yellowish brown, unchanging in colour when injured; tubes 1.6–2 cm in length, yellowish, unchanging in colour when injured. Stipe 12–22 × 0.8–2.8 cm, central, attenuating upward, base enlarged to subglobose; surface viscid, straight or flexuous, pale brown, brown to reddish brown; context yellowish white, unchanging in colour when injured; annulus present, attached to the part near to the apex, sometimes upper surface kept close to the hymenophore, with snake-skin colour pattern on the upside, white on the underside. Basal mycelium white. Odor distinct.

Basidia 29–36 × 12–17 μm, clavate, thin-walled, 4-spored, hyaline to colourless in KOH; sterigmata 4–6 μm in length. Basidiospores [120/6/5] 12–15(–16) × (7.5–)9–11(–12) μm, Q = (1.09–)1.18–1.45(–1.60), Q m = 1.31 ± 0.09, ovoid to broadly ellipsoid, with longitudinal, continuous, occasionally interrupted, 1–1.5 μm height ridges, 7–9 in side-view, cleft at the apex, sometimes cross-striations between longitudinal ridges observed under SEM, olive brown to yellowish brown in KOH. Hymenophoral trama boletoid. Cheilocystidia 24–51 × 10–15 μm, not abundant, subfusiform or fusiform, thin-walled, colourless in KOH, no encrustations. Pleurocystidia 24–70 × 8–20 μm, rare, fusiform or subfusiform, thin-walled, colourless in KOH, no encrustations. Pileipellis an interwoven trichoderm about 350 μm in thickness, embedded in a gelatinized matrix, composed of colourless in KOH, 4–10 μm wide, thin- to slightly thick-walled (up to 0.5 μm) hyphae; terminal cells 22–36 × 5–7 μm, narrowly clavate or subcylindrical, with obtuse apex. Pileal trama made up of hyphae 5–13 μm in diameter, thin- to slightly thick-walled (up to 1 μm), hyaline to colourless in KOH. Stipitipellis an interwoven trichoderm about 100 μm in thickness, embedded in a gelatinized matrix, composed of thin- to slightly thick-walled (up to 0.5 μm), colourless in KOH, occasionally branched, emergent hyphae with narrowly clavate terminal cells (12–50 × 5–7 μm). Stipe trama composed of 5–10 μm wide, cylindrical, thin- to slightly thick-walled (up to 1 μm), hyaline to colourless in KOH, parallel hyphae. Clamp connections absent in all tissues.

Habitat: Solitary or gregarious on the ground in forests of Fagaceae .

Known distribution: Malaysia, Singapore, Japan ( Nagasawa 1997; Halling and Ortiz-Santana 2009), and China.

Materials examined: CHINA. Hainan Province: Qiongzhong County, Yinggeling Nature Reserve , elev. 747 m, 26 July 2009, N. K. Zeng 339 ( HKAS 59808 ) ; same location, elev. 841m, 28 July 2009, N. K. Zeng 381 ( HKAS 59809 ) ; Limushan Nature Reserve, elev. 869 m, 4 August 2010, N. K. Zeng 809 ( HKAS 59810 ). Fujian Province: Zhangping County, Tiantai National Forest Park, elev. 357 m, 4 August 2010, N. K. Zeng 634 ( FHMU). Guangdong Province: Guangzhou City, Tianluhu Forest Park, 29 May 2013, M. Zhang ( GDGM 42849 ) .

Figures

FIGURE 2. Basidiomata of Aureoboletus species. a–d. A. clavatus (a, d from HKAS 59802, holotype; b, c from N.K. Zeng 807-1); e–i. A. longicollis (e, h–i from HKAS 59808; f–g from HKAS 59810) (photo N.K. Zeng).

FIGURE 4. Microscopic features of Aureoboletus longicollis (HKAS 59808). a. Basidia and pleurocystidium. b. Basidiospores. c. Cheilocystidia. d. Pileipellis. e. Stipitipellis. Bars = 10 μm.

FIGURE 5. SEM of basidiospores from dried specimens of Aureoboletus longicollis (HKAS 59808) a. Bar = 10 μm; b. Bar = 5 μm.