Boletus littoreus N.K. Zeng, Y. Wang, C. Xu & Y.Y. Yang, 2022

Yang, Yu-Ying, Xu, Chang, Wang, Yi, Li, Le, Yuan, Lang-Xing, Zhao, Fu-Wei & Zeng, Nian- Kai, 2022, Boletus littoreus (Boletaceae, Boletales), a new species with a white basidioma from Hainan, China, Phytotaxa 554 (2), pp. 176-188 : 182-183

Boletus littoreus N.K. Zeng, Y. Wang, C. Xu & Y.Y. Yang sp. nov. ( Figs. 3–4 )

MycoBank: MB842533

Etymology:—Latin “ littoreus ” refers to the new species growing near the seaside.

Diagnosis:—Differs from closest species of Boletus s. str., viz., B. austroedulis Halling & Fechner (2014: 832) by a stipe without reticulations, a pileipellis composed of elliptic-fusiform to subglobose, sometimes filamentous. hyphae in chains, and an association with trees of Dipterocarpaceae .

Holotype:— CHINA. Hainan Province: Wanning City, Shimei Bay , elev. 5 m, 28 August 2020, L. X. Yuan 3 ( FHMU5919 ). GenBank accession numbers: 28 S = OM 234787 , ITS = OM 234789 , TEF1 = ON 505823 , RPB2 = ON 494596 .

Description:— Basidiomata small to medium-sized. Pileus 4.7–6 cm in diam, subhemispherical at first, then convex to applanate; margin decurved, sometimes slightly uplifted; surface dry, nearly smooth, white (1A1), sometimes staining brown (3C5) when handled; context 0.2–5 mm thick in the center of pileus, white (1A1), unchanging in color when injured. Hymenophore poroid, adnate to slightly depressed around apex of stipe, stuffed with white (1B1) mycelium when young; pores angular, yellow when young, then brownish yellow (1A2), unchanging in color when injured; tubes approximately 4–5 mm in length, yellowish, unchanging in color when injured. Stipe 8.2–9.2 × 0.15–0.7 cm, central, subcylindrical, solid; surface dry, white (1A1) tinged brownish (3C5), without reticulations; context white (1A1), unchanging in color when injured. Basal mycelium whitish (1A1). Odor not distinctive.

Basidiospores [60/3/2] (9–)9.5–11(–11.5) × (4–)4.5–5(–5.5) μm, Q =(1.9–)2–2.40 (–2.5), Qm =2.16 ± 0.142, broadly ellipsoid to cylindrical, slightly thick-walled (<1 μm), olive brown to yellowish brown in KOH, smooth. Basidia 20–25 × 8–11μm, clavate, 4-spored, thin-walled, colorless in KOH; sterigmata 3–5 μm in length. Cheilocystidia 27–72 × 9–13 μm, abundant, subfusiform or fusoid-ventricose, thin-walled, colorless in KOH. Pleurocystidia 40–74 × 7–14 μm, subfusiform or fusoid-ventricose, thin-walled, colorless in KOH. Hymenophoral trama boletoid, made up of hyphae 3–14 μm in diam, thin- to slightly thick-walled (up to 1 μm), colorless in KOH. Pileipellis a trichoderm 100–200 μm in thickness, composed of thin-walled, occasionally branching, colorless to yellowish in KOH, ellipticfusiform to subglobose, sometimes filamentous, hyphae (3–20 μm in diam) in chains; terminal cells 16–75 × 4–12 μm, subclavate, subcylindrical or subfusiform. Pileal trama made up of hyphae 4–15 μm in diam, thin- to slightly thick-walled (<1 μm), colorless to yellowish in KOH. Stipitipellis a hymeniform composed of colorless to yellowish in KOH, thin- to slightly thick-walled (<1 μm) erect hyphae, with clavate, subclavate or subfusiform terminal cells (13–37 × 5–13 μm). Stipe trama made up of longitudinally arranged, parallel hyphae 4–16 μm in diam, cylindrical, thin- to slightly thick-walled (up to 1 μm), colorless in KOH. Clamp connections absent in all tissues.

Habit and habitat:—Scattered on the floor of a forest dominated by Vatica mangachapoi .

Known distribution:—Southern China (Hainan Province).

Additional materials examined:— CHINA. Hainan Province: Wanning City, Shimei Bay , elev. 5 m, 28 August 2020, N. K. Zeng 4861 ( FHMU5923 ) .

Figures

FIGURE 3. Basidiomata of Boletus littoreus. (a, c from FHMU5923; b, d from FHMU5919, holotype). a–c photos by N.K. Zeng; d photo by L.X. Yuan.

FIGURE 4. Microscopic features of Boletus littoreus (FHMU5919, holotype). a. Basidiospores. b. Basidia. c. Cheilocystidia. d. Pleurocystidia. e. Pileipellis. f. Stipitipellis. Bars=10 μm. Drawings by Y. Wang.