Inocybe carpinicola Y.G. Fan, W.J. Yu & P.M. He, 2022

He, Pan-Min, Fan, Yu-Guang, Deng, Lun-Sha & Yu, Wen-Jie, 2022, Inocybe carpinicola (Inocybaceae, Agaricales), a new nodulose-spored species from Hainan Province, China, Phytotaxa 575 (1), pp. 79-88 : 83-85

Inocybe carpinicola Y.G. Fan, W.J. Yu & P.M. He sp. nov. Figs. 2–3

MycoBank: MB 845393

Holotype: — CHINA. Hainan Province: Wuzhishan City, Nansheng Town, Wuzhishan substation of Hainan Tropical Rain Forest National Park , on clay soil under Carpinus L. (1753: 998) forests, at 109°40′43′′E, 18°51′53′′N, 688 m asl., 30 July 2021, leg. W. J. Yu, P. M. He & Y. G. Fan, FYG6307 ( FCAS3513 ); GenBank accession numbers: OP 207874 - ITS, OP 207868 - LSU, OP 227086 - rpb2.

Diagnosis: — This new species can be distinguished from other taxa in the genus Inocybe by brown, smooth- to striped-fibrillose, acutely umbonate, and small-sized pileus; subdistant lamellae with 10–13 attached to the stipe; slender stipes; nodulose to sub-stellate, 7.0–10.0 × 5.5–7.5 μm size basidiospores; sub-fusiform, utriform to clavate pleurocystidia mostly <50 μm in length; the absence of caulocystidia and oily hyphae, and association with Carpinus trees.

Etymology: — referring to its putative host plant, Carpinus londoniana var. lanceolata (Hand. - Mazz.) P. C.Li. (1979: 68).

Description: —Basidiomata small - sized, and slender. Pileus 3–12(17) mm, conical when very young, conicalcampanulate to convex or applanate with a small pointed umbo, occasionally not umbonate but with depression towards the disc when mature; margin slightly incurved, then straight upon maturity; surface dry, smooth-fibrillose to striped-fibrillose, covered with grayish-white (1 B 2) appressed velipellis in young specimens around the center, more sparsely so outwards, fugacious; initially dark brown (6 E 6–6 E 7), then yellowish brown (5 C 6) or brownish yellow (5 C 8), sometimes darker towards the margin (6 E 8). Cortina present at both pileus margin and upper part of stipe in young specimens, fugacious. Lamellae adnexed, sub-distant, 1–1.5 (2) mm in width, unequal with 10–13 attached to the stipe, alternately distributed with 3–4 tiers of lamellulae, edge indistinctly fimbricate, nearly concolorous with the face; white to ivory white (1 A 1–1 B 1) at first, then beige (1 B 2–1 B 3) to brownish (4 B 8), brown (5 B 7–5 C 8) to dark brown (6 C 7–6D8) when mature. Stipe 15–40 mm long, 0.8–1.5 mm wide, terete, solid, equal with a slightly swollen base, pruinose at the extreme apex, covered with a heavy partial veil and a dense appressed whitish vesture downwards, background pale yellowish (5 B 5–5 B 6) when young, brownish (5 B 7) at maturity. Context fleshy, white (1 A 1) to beige (1 B 2–1 B 3) with a brownish tinge (5 C 8) in pileus, 0.2–0.4 mm thick at mid-radius, 1–1.3 mm under the umbo; fibrillose in stipe, brownish (5 B 5), striate, shiny. Odour indistinct.

Basidiospores [100/4/2](7.0)7.5– 8.4 –9.2(10.0) × (5.5)5.8– 6.3 –7.0(7.5) μm, Q ＝(1.07)1.10– 1.32 –1.50(1.61), Q m ± SD ＝1.32 ± 0.0107; nodulose to sub-stellate, with 7–9 prominent nodules, apiculus small and indistinct, yellowish to goldish in 5% KOH, with one intracellular ellipsoid oily content. Basidia 20–28 × 7–11 μm, slenderly clavate to clavate, occasionally broadly clavate, obtuse at apex, tapered downwards, some with oily contents of different sizes, with 4- or 2- sterigmata 3–5 mm length, colorless or yellowish. Pleurocystidia 41–52 × 11–20 μm, sub-fusiform, utriform to broadly clavate, apices rounded or obtuse, often with crystals, base tapered into pedicel or occasionally truncate, slightly thick-walled, walls yellowish, 0.5–1 μm thick; colorless but with yellowish contents. Cheilocystidia 33–50 × 12–19 μm, resemble pleurocystidia, clavate or fusiform, walls yellowish, up to 1 μm thick. Hymenophoral trama 50–77 μm thick, sub-regularly arranged, yellowish in mass, composed of cylindrical or inflated hyphae measured 3–9 μm or 11–25 μm wide, respectively, smooth, colorless to yellowish, thin-walled. Pileipellis a cutis, 30–52 μm thick, brownish in mass, composed of cylindrical to inflated hyphae 4–20 in width, incrusted, thin-walled, walls yellowish. Pileal trama colorless or yellowish, sub-regular, hyphae inflated, colorless, 13–19 μm wide. Stipitipellis a cutis, regular, hyphae thin-walled, incrusted, and yellowish to yellow. Stipe trama regularly arranged, composed of colorless to yellowish, thin-walled, incrusted hyphae 4–15 μm wide. Caulocystida, cauloparacystidia, and oily hyphae not observed. Clamp connections present in all tissues.

Habitat and ecology: — Scattered on clay soil under Carpinus londoniana var. lanceolata . Fruits in July to August in tropical China.

Distribution: — Known only from the type locality, Hainan Province of China.

Additional specimens examined: — CHINA. Hainan Province: Wuzhishan City, Nansheng Town , Wuzhishan substation of Hainan Tropical Rain Forest National Park , on clay soil under Carpinus forests, at 109°40′43′′E, 18°51′53′′N, 690 m asl., 29 July 2021, leg. Y.- G. Fan , L.- S. Deng , L.- N. Zhao , J.- H. Hu , FYG6297 ( FCAS3617 ), FYG6300 ( FCAS3618 ), 30 August 2021, leg. W.-J. Yu, P.-M. He, Y.-G. Fan, FYG6312 ( FCAS3620 ), FYG6315 ( FCAS3621 ), W.- J. Yu & Y.- G. Fan, FYG6381 ( FCAS3622 ) .

Figures

FIGURE 2. Basidiomata of Inocybe carpinicola. a–b. FYG6297 (FCAS3617). c–g. FCAS6307 (FCAS3619, holotype). d-g. FCAS3154. Photos by Y.G. Fan.

FIGURE 3. a–b. Basidiospores. c–d. Basidia e. Pleurocystidia. f. cheilocystidia and cheiloparacystidia. g. Pileipellis. h. Hymenophoral trama. i. Stipitipellis hyphae. J. Stipe trama hyphae. K. Stipitipellis. Scale Bars: a–h = 10 μm. Photo by P.M. He