Inocybe ornata E. Horak, Matheny & Desjardin, 2015

Horak, Egon, Matheny, P. Brandon, Desjardin, Dennis E. & Soytong, K., 2015, The genus Inocybe (Inocybaceae, Agaricales, Basidiomycota) in Thailand and Malaysia, Phytotaxa 230 (3), pp. 201-238 : 226-227

16. Inocybe ornata E. Horak, Matheny & Desjardin , spec. nov. Fig. 15a–h ; Pl. 8h

MycoBank MB 519917

Etymology: ornatus (Lat.), ornate.

Diagnosis: Pileus 20–45 mm wide, pale cinnamon, argillaceous or pale ochre, disc with umber brown tinge; surface smooth, viscid when moist; margin non-striate and not splitting, with persistent whitish appendiculate veil remnants. Lamellae pallid at first, slowly becoming cinnamon to beige brown. Stipe 20–60 × 3.5–5 mm, with a marginate basal bulb up to 10 mm wide, surface entirely pruinose, whitish, cortina absent, margin of base covered by conspicuous whitish persisting fibrillose appendiculate volva-like veil remnants. Basidiospores 6–8 × 4.5–5.5 μm, ovoid, with low hemispheric nodules. Cheilocystidia, pleurocystidia, and caulocystidia 45–65 × 11–17 μm, fusoid, walls up to 3 μm thick, hyaline. In tropical lowland forest dominated by Dipterocarpaceae , Thailand.

Holotype:— THAILAND. Mae Hong Son Prov.: S of Mae Hong Son, Hwy. 108, 247 km marker, ca. 425 m elev., on lateritic soil in tropical lowland forest (dominated by Dipterocarpus obtusifolia , mixed with Tectona grandis ), 1 Jul. 2002, leg. E. & A. Horak (ZT10107, holotype) GenBank accession no. GQ892975.

Pileus 20–45 mm wide, at first hemispherical to convex with incurved margin, in age becoming campanulate to umbonate-expanded; pale cinnamon, argillaceous or pale ochre, disc with umber brown tinge; surface smooth, viscid if moist, non-striate and non-splitting margin with conspicuous, appendiculate whitish or pallid, fibrillose, persisting veil remnants. Lamellae 32–40 reaching stipe, 3–7 lamellulae, moderately close to close, adnexed to short-marginate, ventricose, up to 5 mm broad; at first pallid slowly becoming cinnamon to beige-brown in mature specimens, edges white and fimbriate. Stipe 20–60 × 3.5–5 mm, cylindrical, equal then gradually enlarging into distinctive bulbousmarginate base (up to 10 mm wide), whitish; surface dry, pruinose all over, margin of base covered by conspicuous whitish persisting fibrillose appendiculate volva-like veil remnants; cortina absent; context solid, whitish, unchanging upon exposure. Odor weakly spermatic. Taste like odor.

Basidiospores 6–8 × 4.5–5.5 μm, ovoid, nodulose, hemispherical projections (nodules) rather inconspicuous, up to 1.5 μm high, yellow-brown, brown in deposit. Basidia 20–26 × 7–8 μm, 4-spored, slender clavate. Cheilocystidia 45–65 × 11–17 μm, fusoid, metuloid, walls up to 3 μm thick at apex, hyaline, crystals present; paracystidia 15–20 × 8–10 mm, clavate to vesiculose, hyaline, thin-walled. Pleurocystidia size and shape like cheilocystidia. Caulocystidia similar to cheilocystidia, intermixed with paracystidia-like cells. Hyphae of stipe 4–12 μm wide, encrusted with pigment. Pileipellis an (ixo)cutis of repent, cylindrical hyphae, 2–4 μm wide, terminal cells not differentiated, weakly gelatinized hyaline and smooth thin wall; subcutis hyphae cylindrical, 5–10 μm wide, encrusted with pale yellow-brown pigment; oleiferous hyphae absent. Clamp connections present.

Habitat: On lateritic soil in tropical lowland forest (dominated by Dipterocarpus obtusifolia , mixed with Tectona grandis ), ca. 425 m elev.

Known distribution: Northwest Thailand.

Notes: Among all representatives of Inocybe recorded so far in Thailand and Malaysia, I. ornata is outstanding due to the significant cup-shaped and marginate base of the stipe, the margin of which is appendiculate from volva-like, persistent, white velar remnants. In fresh specimens the pileus surface is densely covered with innately fibrillose and weakly gelatinized hyphae from the universal veil (velipellis), and the whitish stipe is pruinose over the entire length. The microscopical characters are insignificant except for the medium-sized basidiospores with rather low hemispherical nodules. The LSU sequence of the type (ZT10107) is poorly placed and divergent from other sequences in the Inocybe clade. Affiliation with other species is not well-known at this time.

Figures

PLATE 8. SEM images. a. Basidiospores of Inocybe hydrocybiformis (ZT10077); scale bar = 2 μm. b. Basidiospores of Inocybe stellata (ZT10097, holotype); scale bar = 2 μm. c. Basidiospores of Inocybe thailandica (DED8049, holotype); scale bar = 5 μm. d. Hymenial cystidia of Inocybe angustifolia (ZT10149); scale bar = 10 μm. e. Basidiospores of Inocybe brevisquamulosa (ZT10102, holotype); scale bar = 2 μm. f. Basidiospores of Inocybe pusillima (ZT10130); scale bar = 2 μm. g. Basidiospores of I. fragilissima (DED8061, holotype); scale bar = 2 μm. h. Basidiospores of Inocybe ornata (ZT10107, holotype); scale bar = 3 μm. i. Basidiospores of Inocybe parvibulbosa (ZT10099, holotype). Scale bar = 2 μm. Photos by U. Jauch & M Kirchmair.

FIGURE 15. Macroscopic and anatomical features for Inocybe ornata (ZT10107, holotype). a. Basidiomes. b. Basidiospores. c. Basidia. d. Cheilocystidia. e. Paracystidia. f. Pleurocystidia. g. Caulocystidia. h. Pileipellis. Scale bars: basidiomes = 20 mm, basidiospores = 10 μm, basidia and cystidia = 20 μm, pileipellis = 40 μm. Drawings by Egon Horak.