Inocybe squarrosofulva S.N. Li, Y.G. Fan & Z.H. Chen, 2021

Li, Sai Nan, Xu, Fei, Jiang, Ming, Liu, Feng, Wu, Fang, Zhang, Ping, Fan, Yu Guang & Chen, Zuo Hong, 2021, Two new toxic yellow Inocybe species from China: morphological characteristics, phylogenetic analyses and toxin detection, MycoKeys 81, pp. 185-204 : 185

Inocybe squarrosofulva S.N. Li, Y.G. Fan & Z.H. Chen sp. nov.

Figures 4 , 5 , 6b

Etymology.

Squarrosus (Latin), squamous; Squarrosus fulvus (Latin), brown-orange, referring to its pileus.

Holotype.

China. Hunan Province: Zhangjiajie, Badagongshan National Nature Reserve, 29°67.57'N, 109°74.45'E, alt. 1600 m, on ground in subtropical montane forest, 29 July 2019, Z.H. Chen and S.N. Li, MHHNU31548 (GenBank accession no. ITS: MZ050799; nrLSU: MW715814; rpb2: MW574997).

Diagnosis.

Small to medium-sized basidiomata. Orange-brown to dark brown pileus with squarrose scales. Yellowish brown to brownish, adnexed lamellae. Stipe equal, stout, with distinctly filamentous annulate cortina, pruinose at apex. Odor like raw potatoes. Nodulose basidiospores with six nodules. Hymenial cystidia are broadly fusoid to lageniform, thick-walled. Differs from Inocybe squarrosolutea in its orange-brown to dark brown pileus, distinctly filamentous annulus, and less nodulose basidiospores.

Basidiomata.

Small to medium-sized. Pileus 25-55 mm in diameter, spherical to bell-shaped when young, and gradually flattened to hemispheric or convex; margin strongly in-rolled when young then decurved or slightly uplifted; yellowish (2A5), center covered with yellow ochre (5C7) to brownish yellow (5C8) erect conical fibrillose scales (up to 1.5 mm high, 1-1.5 mm wide), coarsely fibrillose-rimose towards the margin; pileus with crenellated, nonpersisting fibrillose veil remnants at margin. Lamellae adnexed, crowded (ca. 55-70), up to 4 mm wide; yellowish brown (4C7), becoming brownish (5E4) with age, edge concolorous. Stipe 40-80 × 5-8 mm, cylindrical, equal or slightly enlarged at the base, solid; light yellow (2A3) to yellow ochre (5C7); pruinose with few yellowish-brown (4C7) furfuraceous scales at apex; towards the base covered with numerous, yellow-ochre (5C7), woolly-fibrillose, incomplete zones; dry. Cortina conspicuous, annulate, composed of yellow ochre (5C7) fibrils, and remains at the upper part of the stipe. Context: pale yellow (2A5) in pileus and stipe. Odor like raw potatoes.

Basidiospores.

(4.5) 5.0-7.0 µm (av. 6.6 μm, SD 1.0 μm) × 4.0-6.0 (7.0) (av. 5.3 μm, SD 0.8 μm) µm, Q = (1.00) 1.10-1.67 (1.75), Qm = 1.26 ± 0.16 (n = 80 of 4 coll.), nodulose with six hemispheric knobs, yellowish-brown with 5% KOH, containing a bright yellow oil droplet of uniform size inside. Basidia: 18-24 × 8-10 µm, 4-spored, clavate to broadly clavate. Pleurocystidia: 36-49 µm (av. 43.8 μm, SD 3.9 μm) × 13-18 µm (av. 15.5 μm, SD 2.6 μm), Q = 2.12-3.46 (n = 30 of 2 coll.), mostly hyaline, few with bright yellow oily inclusions, fusiform to broadly fusiform, with crystalliferous apices, obtuse or truncated at base; thick-walled, walls bright yellow with 5% KOH, up to 2 µm thick towards apex. Cheilocystidia: 30-48 × 9-19 µm, similar to pleurocystidia, hyaline. Cheiloparacystidia: 10-23 × 6-12 µm, abundant among cheilocystidia, obovate, elliptic to clavate, thin-walled, hyaline. Hymenophoral trama: regular to subregular, composed of inflated hyphae, up to 18 μm wide, hyaline to lightly yellow with 5% KOH, thin-walled. Pileipellis: a trichoderm, subregular, consisting of cylindrical hyphae 5-13 µm in diameter, walls pale yellow brown with 5% KOH, smooth, thin-walled. Caulocystidia: present at stipe apex, 23-49 × 9-21 μm, in clusters, thick-walled, walls thinner than pleurocystidia, hyaline or with pale yellow intracellular contents. Cauloparacystidia: 8-19 × 3-10 μm, clavate or broadly clavate, hyaline, thin-walled. Oleiferous hyphae present in pileus and stipe trama, 4-11 μm in diameter, branched. Clamp connections seen on all hyphae.

Habitat.

On soil in subtropical montane forest dominated by Fagus lucida .

Known distribution.

Known from the type locality.

Other examined specimens.

27 July 2020, Z.H. Chen and S.N. Li, MHHNU31927.

Figures

Figure 4. Basidiomata of Inocybe squarrosofulva a, b MHHNU 31548 c, d MHHNU 31927. Scale bars: 10 mm.

Figure 5. Microscopic features of Inocybe squarrosofulva (MHHNU 31548, holotype) a, b basidiospores, c basidia with probasidium d gill edge e pleurocystidia f cheilocystidia and paracystidia g caulocystidia and cauloparacystidia h oleiferous hyphae i hymenial hyphae, and j, k pileipellis. Scale bars: 10 µm.

Figure 6. SEM images showing basidiospores of a Inocybe squarrosolutea b Inocybe squarrosofulva. Scale bars: 5 µm.