Chalciporus citrinoaurantius Ming Zhang & T.H. Li, 2017

Zhang, Ming, Li, Tai-Hui & Song, Bin, 2017, Two new species of Chalciporus (Boletaceae) from southern China revealed by morphological characters and molecular data, Phytotaxa 327 (1), pp. 47-56 : 49-50

Chalciporus citrinoaurantius Ming Zhang & T.H. Li sp. nov.

MycoBank: MB821522

Etymology: citrino - means lemon yellow and aurantius means orange color, therefore, citrinoaurantius refers to the lemon yellow to orange hue of the pileus color.

Diagnosis:—This species is similar to C. rubinelloides , but differs in the smaller basidiomata with light yellow to grayish orange pilei, larger pores, and smaller basidospores (9.0)9.5–12.5(13) × 3–4(4.5) μm. The light orange to rose pink tubes unchanging when bruised and the yellowish stipe context changing to light yellow when exposed are also distinguishing features.

Type:— CHINA. Hunan Province, Chenzhou City, Yizhang county, Mangshan National Natural Reserve, at 24°57′N, 112°56′E, alt. 1300 m, 14 June 2015, Ming Zhang (GDGM 44776, holotype!).

Description: —Basidiomata small. Pileus 2–5 cm wide, hemispheric at first, then becoming convex to nearly plane with age, occasionally turning upwards at the margin when mature, fleshy, surface dry, viscid when wet, smooth or velvety-tomentose, light yellow, lemon yellow, light orange, grayish yellow to grayish orange (1A5–6A5, 1B5–6B5). Context 2–4 mm thick at stipe, soft, white, yellowish white to pale yellow (1A1–3A1, 1A2–3A2, 1A3–3A3), unchanging when exposed to air. Tubes 3–5 mm deep, depressed to subdecurrent, light orange, pastel red to rose pink (6A5–11A5), often with purplish hue, color unchanging when bruised. Pores 1–1.5 mm in diam, circular to angular, pore surface concolorous with tubes, unchanging when bruised. Stipe 30–40 × 3–5 mm, central, solid, subcylindrical or clavate, equal or slightly tapered downward, concolorous with pileus or paler, surface smooth or pruinose at apex or upper half, sometimes with indistinct longitudinal striations when mature; stipe context yellowish white to pale yellow (2A2–3A2, 2A3–3A3), changing to light yellow (2A5–3A5) when exposed, then partially becoming concolorous with stipe surface or nearly so; basal mycelium yellowish white, yellow to golden yellow. Odor indistinctive and taste slightly peppery.

Basidiospores [80/4/4] (9.0)9.5–12.5(13) × (3)3.5–4(4.5) μm, [Q = (2.5)2.7–3.25(3.4), Qm = 2.96± 0.21], fusiform, cylindrical to somewhat oblong, barely inequilateral in profile, smooth, thin-walled, yellowish to yellowish brown in 5% KOH, yellow brown to dark brown in Melzer’s reagent. Basidia 23–32 × 8–10 μm, 4-sterigmate, clavate, yellowish white to hyaline in 5% KOH. Pleuro- and cheilocystidia 30–65 × 8–13 μm, scattered, projecting and conspicuous, narrowly fusiform, thin-walled, smooth, yellowish white to hyaline, and usually containing some yellowish brown oleiferous scattered substance in 5% KOH. Hymenophoral trama subparallel, yellowish white to hyaline in 5% KOH, with hyphae 6–10 μm broad. Pileipellis a trichoderm of erect hyphae 4–7 μm in diam, branched, yellowish white to hyaline in 5% KOH, dark brown to rusty brown in Melzer’s reagent; terminal elements cylindrical, clavate or nearly fusoid. Stipitipellis a tangled layer of repent hyphae 3–7 μm in diam, yellowish white to hyaline in 5% KOH. Clamp connections absent in all tissues.

Habit, habitat and distribution:—Solitary or scattered on humus and debris under Pinus massoniana Lamb and mixed with other broadleaf trees, alt. 1000–1500 m; June to September, currently known from Hunan and Zhejiang Province.

Additional specimens examined:— CHINA. Hunan Province, Chenzhou City, Yizhang county, Mangshan National Natural Reserve , at 24°57′N, 112°56′E, alt. 1300 m, 14 June 2015, Ming Zhang ( GDGM44717 ) ; Same locality, 19 May 2015, Ming Zhang ( GDGM44480 ) ; Same locality and date, Ming Zhang ( GDGM44481 ) ; Zhejiang Province, Longquan county, Fengyangshan National Natural Reserve , at 27°56′N, 119°12′E, alt. 1000 m, 11 September 2016, Ming Zhang ( GDGM46540 )