Butyriboletus brunneoides L. Fan & H.Y. Fu, 2022

Fu, Hao-Yu, Li, Ting & Fan, Li, 2022, Two new species of Butyriboletus from China, Phytotaxa 544 (2), pp. 207-219 : 213-215

Butyriboletus brunneoides L. Fan & H.Y. Fu , sp. nov. 1 ( Fig. 3 )

Mycobank:—MB842144

Diagnosis:—differs from Bu. brunneus in the small to medium basidiome with a smooth pileus, a thin stipe that develops reddish stains at the base and the isolated phylogenetic position.

Etymology:—‘ brunneoides ’, refers to the similarity to Bu. brunneus .

Holotype:— CHINA. Shanxi Province, Jincheng City, Qinshui County, Shangwoquan village , 35°35ʹ1ʺN, 112°4ʹ37ʺE, elev. 1150 m, on the ground under Quercus spp ., 26 July 2021, collected by Jingchong Lv LJC045 ( BJTC FM1816 ).

Description:— Pileus 3.5–9.4 cm in diam., hemispherical to convex, becoming broadly convex when mature; surface dry, smooth, yellowish brown (#ffbb78) to brown (# c96400), margin decurved; context firm and dense, thick, pale yellow (#ffff68) to yellow (#fffc9a), unchanging when exposed, or turning very slightly pale blue over the tubes. Hymenophore (tube layer) bright yellow (#ffff1a) to light yellow (# eaff80), changing blue when exposed; pores circular to somewhat elliptical, 0.2–0.3 mm in diam; tubes 2–5 mm deep. Stipe 4.5–6 × 0.7–3 cm, cylindrical, equal, widening towards the base, dry, solid, covered with a fine yellow reticulum; pale yellow (# eaff80), developing pale red stains near the base changing blue when bruised; annulus absent. Basal mycelium whitish (#ffffff) to pale yellow (#fff281). Odor distinct like salted fish when dry. Taste unpleasant, typically bitter or somewhat tart.

Basidiospores [40/2/2] 11–15(–17) × 3–5 [Q = 3.25–3.75 (4.33), Q m = 3.5 ± 0.25], subfusiform, subhyaline in KOH. Basidia 27.5(–15)–35 × 7.5–10 μm, clavate, thin-walled, 4-spored; sterigmata short. Hymenophoral trama boletoid. Pleurocystidia 35–45 × 8–12.5 μm, smooth, thin-walled, hyaline in KOH, fusoid-ventricose to broadly clavate with subacute apex; cheilocystidia 30–32.5 × 7.5–10 μm, smooth, thin-walled, hyaline in KOH, narrowly clavate to clavate-ventricose. Pileipellis an interwoven trichoderm 37.5–50 μm thick, composed of interwoven hyphae 2.5–5 μm in diam., hyphae yellowish brown (#edb849), hyaline in KOH, smooth, thin-walled, terminal cells cylindric with subglobose or rounded apices. Stipitipellis an interwoven trichoderm-like structure 105–200 μm thick, composed of thin- to slightly thick-walled (up to 1 μm) hyphae with narrowly or broadly clavate, subfusiform or fusiform terminal cells (16–26 × 4–9 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 3–14 μm diam. Clamp connections absent.

Habit, habitat and distribution: solitary or scattered, on ground in a Fagaceae forest, currently only known from Shanxi Province, North China.

Figures

FIGURE 3. Morphological features of Butyriboletus brunneoides. a. Basidiomes (BJTC FM1816, holotype), b. Stipitipellis. c. Pileipellis d. Basidiospores e. Cheilocystidia f. Basidia and a pleurocystidium g. Pleurocystidia. Scale bars: a = 2 cm, b, c = 20 μm, d, e, f = 5 μm, g = 10 μm. Drawings by Haoyu Fu.