Inosperma hainanense Y.G. Fan, L.S. Deng, W.J. Yu & N.K. Zeng, 2021

Deng, Lun-Sha, Kang, Rui, Zeng, Nian-Kai, Yu, Wen-Jie, Chang, Cheng, Xu, Fei, Deng, Wang-Qiu, Qi, Liang-Liang, Zhou, Yu-Ling & Fan, Yu-Guang, 2021, Two new Inosperma (Inocybaceae) species with unexpected muscarine contents from tropical China, MycoKeys 85, pp. 87-108 : 87

Inosperma hainanense Y.G. Fan, L.S. Deng, W.J. Yu & N.K. Zeng sp. nov.

Figures 4 , 5

Etymology.

" hainanense " refers to the its type locality.

Holotype. China, Hainan Province, Changjiang Li Autonomous County, Bawangling substation of Hainan Tropical Rainforest National Park, under Castanopsis dominated forest, at 19°7'12.43"N, 109°7'6.29"E, alt. 630 m, 2 September, 2020, N.K. Zeng, Zeng4937 (FHMU3166), GenBank accession number: ITS (MZ374070); LSU (MZ374761) and rpb2 (MZ388104).

Diagnosis.

Distinguishes from I. muscarium by its slender basidiomata, ellipsoid to ovoid basidiospores, and mostly vesiculose cheilocystidia.

Basidiomata.

small to medium-sized. Pileus 25-53 mm diam., conical to convex at young age, becoming applanate to uplifted with age, with a broad to subacute umbo, margin initially decurved, straight to somewhat wavy when mature; surface dry, smooth when young, fibrillose-rimulose elsewhere, strongly rimose towards the margin with age; chocolate brown (5D8) to somewhat dark brown (5F7) around the disc, straw yellow (4A6) to yellowish brown (4B5) elsewhere, background pallid to cream white (4B1), becoming brown (5B4) to dark brown (5C6) with age; Lamellae rather crowded, adnexed, initially ivory white (5A1) to grayish white (5B2), becoming dirty yellowish (5B5) to brownish (5C7) when matured, completely brown (5D6) after drying, 2-3 mm in width, edge fimbriate, slightly serrate. Stipe 40-72 × 3-5 mm, central, nearly terete, equal with a slightly swollen apex, base somewhat swollen; nearly smooth and longitudinally striate all over the stipe; initially ivory (5A1) to yellowish white (5A2) at the upper half, yellowish to brownish (4B5) downwards, becoming uniformly yellowish brown (4B7) to brown (4C7) with age. Context solid, fleshy in pileus, white to grayish white (4B1), pale brown under the umbo (4B2), 1-2 mm thick at mid-radius, 4-5 mm thick under the umbo, fibrillose in stipe, pallid to yellowish (4A2) or brownish (4B2), striate, shiny. Odor indistinct or slightly acid.

Basidiospores.

[180/9/9] 8-9(10.5) × 5-7 μm, Q = (1.18)1.28-1.64 (1.78), Qm = 1.43, mostly ellipsoid to ovoid, occasionally subphaseoliform, smooth, slightly thick-walled, brown to yellowish brown, apiculus small, indistinct, with a spherical to ellipsoid yellowish brown oil-droplet. Basidia 21-28 × 6-9 μm, clavate, often obtuse at apex, slightly tapered towards the base, thin-walled, 4-spored, sometimes 2-spored, sterigmata 4-6 μm in length, with spherical yellowish brown to golden yellow brown oily inclusions. Pleurocystidia absent. Lamella edge sterile. Cheilocystidia 34-55 × 15-25 μm, abundant and crowded, mostly obovoid to balloon-shaped, occasionally broadly clavate, rarely enlongate-clavate, thin- to slightly thick-walled (up to 1 μm thick); often rounded or slightly obtuse at apex, colorless to pale yellow, sometimes with golden yellow pigments. Hymenophoral trama 75-138 μm thick, sub-regular, hyaline to slightly yellow, composed of cylindric to inflated hyphae 20-33 μm wide, slightly constricted at septa. Pileipellis a cutis, hyphae 2.5-10 μm wide, thin-walled, pale yellow to yellowish brown, cylindrical, sometimes slightly encrusted. Pileal trama regular to subregular, hyphae 12-30 μm wide, thin-walled, colorless. Stipitipellis a cutis, regularly arranged, walls yellowish to bright yellow. Oleiferous hyphae 2.5-10 μm wide, commonly scattered in pileus and stipe tramal tissues, straw yellow or bright golden yellow, smooth, often bent or diverticulate. Clamp connections observed in all tissues.

Habitat.

Scattered or gregarious in small clusters under Castanopsis dominated forest, June to September in tropical China.

Known distribution.

China (Hainan, Guangdong).

Additional materials examined.

China. Hainan Province, Wuzhishan City, Maoyang Town , Maoyang Village , 11 August 2021, Y.G. Fan & L.S. Deng, FYG6440 (FHMU6513); Ganshiling Provincial Nature Reserve , L.S. Deng & Y.G. Fan, DLS0043 (FHMU6512); Changjiang Li Autonomous County, Bawangling substation of Hainan Tropical Rainforest National Park , under Castanopsis dominated forest, 2 September 2020, N.K. Zeng, Zeng 4936 (FHMU3165); Zeng 4935 (FHMU3167) ; Guangdong Province, Guangzhou City, Tianluhu Forest Park, 2 June 2019, Y.G. Fan & W.J. Yu, FYG4386 (FHMU3168); Shaoguan City, Danxiashan Nature Reserve , 4 June 2019, Y.G. Fan & W.J. Yu, FYG4388 (FHMU3175); 4390 (FHMU3169); FYG4394 (FHMU3170) .

Muscarine detection

Representative chromatograms of muscarine were shown in Fig. 8 . The muscarine toxin content was confirmed by linear equation according to the analysis of UPLC-MS/MS, it was found that both of the two new species contained muscarine toxin, and the content of Inosperma muscarium was 16.03 ± 1.23 g/kg while I. hainanense was 11.87 ± 3.02 g/kg. Muscarine was identified by comparing retention time (1.22 min) and relative deviation (0.82%) in the allowable relative range of 25 % base on the qualitative analysis. The calibration curve for muscarine generated during the validation was y = 2083.17 x -209.297 (r = 0.9988) for muscarine concentration in the range of 2-200 ng/mL (y represents the peak area, and x is muscarine concentration, r is correlation coefficient). Recovery of muscarine ranged from 93.45% to 97.25%, and the average recovery was 95.56%.

Figures

Figure 4. Basidiomata of Inosperma hainanense a-e basidiomata f-g rimose to rimulose pileus h lamellae i lamellae edge j-k stipe surface. c FHMU 3166 (holotype) a-b, d-g, i-k FHMU 6511 h FHMU 3168. Scale bars: 10 mm (a-k). a-b, d-k: photos by L. - S. Deng; c: photos by N. - K. Zeng

Figure 5. Microscopic features of Inosperma hainanense (FHMU 3166, holotype) a-b basidiospores c-d basidia e-k cheilocystidia in clusters l pileipellis and pileal trama n hymenophoral trama m, o oleiferous hyphae p stipitipellis and stipe trama. Scale bars: 10 μm (a-k). Photos by L. - S. Deng

Figure 8. Representative chromatograms of muscarine.