Neoboletus multipunctatus N.K. Zeng, H. Chai & S. Jiang

Chai, Hui, Liang, Zhi-Qun, Xue, Rou, Jiang, Shuai, Luo, Shi-Hong, Wang, Yong, Wu, Lu-Ling, Tang, Li-Ping, Chen, Yun, Hong, Deng & Zeng, Nian-Kai, 2019, New and noteworthy boletes from subtropical and tropical China, MycoKeys 46, pp. 55-96 : 71

7. Neoboletus multipunctatus N.K. Zeng, H. Chai & S. Jiang sp. nov. Figures 5 g–l, 12

Typification.

CHINA. Hainan Province: Qiongzhong County, Yinggeling National Nature Reserve, elev. 800 m, 3 August 2015, N.K. Zeng 2498 (FHMU 1620, holotype). GenBank accession numbers: 28S = MH879693, ITS = MH885354, tef1 = MH879722.

Etymology.

Latin, “multipunctatus”, referring to the many punctuations on the stipe.

Description.

Basidiomata medium-sized. Pileus 5.7-7 cm in diameter, convex to applanate; surface dry, finely tomentose, brown (4D7), dark brown (5C7) to blackish brown (5D5); context 1-1.5 cm thick in the center of the pileus, yellowish (1A5), changing blue quickly when injured. Hymenophore poroid, depressed around apex of stipe; pores subround, 0.3-0.4 mm in diameter, brown (7B5) to reddish brown (6C8), changing bluish black quickly when injured; tubes 0.5-0.7 cm in length, yellowish (1A5), changing blue quickly when injured. Stipe 7-7.4 × 1-1.3 cm, central, subcylindric, solid, usually flexuous; surface dry, covered with reddish-brown (7B5) squamules; context yellow (1A3), changing blue (21B3) quickly when injured; basal mycelium yellow (1A3). Odor indistinct.

Basidia 27-37 × 6-10 μm, clavate, thin-walled, colorless to yellowish in KOH; four-spored, sterigmata 5-6 μm in length. Basidiospores [80/4/3] 8.5 –11(– 12) × 4-5 μm, Q=(1.80 –)1.90–2.50(– 2.75), Qm=2.22 ± 0.22, subfusoid and inequilateral in side view with a weak or distinct suprahilar depression, elliptic-fusiform to subfusiform in ventral view, slightly thick-walled (to 0.5 μm), olive-brown to yellowish brown in KOH, smooth. Hymenophoral trama boletoid; composed of colorless to yellowish in KOH, 4-8 μm wide, thin-walled hyphae. Cheilocystidia 27-34 × 5-7 μm, fusiform or subfusiform, thin-walled, fawn to tawny in KOH, no encrustations. Pleurocystidia 38-61 × 6-8 μm, fusiform or subfusiform, thin-walled, colorless to tawny in KOH, no encrustations. Pileipellis a trichoderm about 120 μm thick, composed of vertically arranged, nearly colorless to yellowish in KOH, 3-5 μm wide, thin-walled hyphae; terminal cells 21-70 × 3-5 μm, clavate or subclavate, with obtuse apex. Pileal trama made up of hyphae 3-8 μm in diameter, thin-walled, colorless to yellowish in KOH. Stipitipellis hymeniform about 100 μm thick, composed of thin-walled emergent hyphae, colorless to yellowish in KOH, with clavate, subclavate, fusiform or subfusiform terminal cells (25-44 × 3-9 μm), and occasionally with scattered clavate, 4-spored basidia. Stipe trama composed of longitudinally arranged, parallel hyphae 4-9 μm wide, cylindrical, thin to slightly thick-walled (to 0.5 μm), colorless in KOH. Clamp connections absent in all tissues.

Habitat.

Solitary on the ground in forests dominated by fagaceous trees including Lithocarpus spp.

Distribution.

Southern China.

Additional specimens examined.

CHINA. Hainan Province: Changjiang County, Bawangling National Nature Reserve, elev. 600 m, 22 August 2009, N.K. Zeng 559 (HKAS 76851); Ledong County, Yinggeling National Nature Reserve, elev. 620 m, 6 May 2018, N.K. Zeng 3324 (FHMU 2808).

Note.

Neoboletus multipunctatus is characterized by a brown, dark brown to blackish brown pileus, brown to reddish-brown pores changing bluish black when injured, stipe surface densely covered with brown to reddish-brown punctuations, smaller basidiospores, and its association with fagaceous trees. It is both morphologically similar and phylogenetically related to N. brunneissimus (W.F. Chiu) Gelardi et al. (Fig. 2), a species originally described from Yunnan Province of southwestern China. However, N. brunneissimus has larger basidiospores measuring 10-14 × 4.5-5 μm, and it occurs in temperature regions in addition to subtropical belts ( Wu et al. 2016a). Neoboletus multipunctatus is also similar to N. hainanensis and N. sinensis (T.H. Li & M. Zang) Gelardi et al. morphologically. However, both pileal and stipe surface of N. hainanensis stain blue when injured, with white basal mycelium on the stipe, relatively larger basidiospores measuring 9.5-13.5 × 4-5 μm, and a trichodermium to ixotrichodermium pileipellis ( Zang et al. 2001; Wu et al. 2016a). Neoboletus sinensis , a species also described from Hainan Province, has a cherry red stipe with reticulations, larger basidiospores measuring 13-19 × 5-6.5 μm, and wider cystidia ( Zang et al. 2001; Vizzini 2014).