Inocybe errata 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 : 210

5. Inocybe errata E.Horak, Matheny & Desjardin , spec. nov. Fig. 6a–e ; Pl. 2c

MycoBank MB 519912

Etymology: erratus (Lat.), deceiving, false.

Diagnosis: Pileus warm brown, hazel brown, pale golden brown or orange-brown, covered all over with fibrillose squamules or minute scales, dry. Lamellae adnate. Stipe equal, not longer than pileus diameter, surface not pruinose in any part; cortina conspicuous, persistent, annulate, present as belts and scaly zones of veil tissue towards base. Odor not distinctive. Basidiospores amygdaliform, smooth. Pleurocystidia absent. Cheilocystidia broadly clavate or vesiculose. On lateritic soil in tropical submontane conifer forest dominated by Pinus kesiya , P. merkusii and dipterocarp forest dominated by Dipterocarpus obtusifolia , Thailand and India.

Holotype:— THAILAND. Chiang Mai Prov.: Orb Luang , on lateritic soil in tropical submontane conifer forest ( Pinus merkusii , pure stand in plantation), 2 Jul. 2002, leg. E. & A. Horak ( ZT10108 , holotype) GenBank accession no. GQ892935.

Pileus 10–40 mm wide, at first hemispherical or convex with incurved non-striate margin, becoming expanded in age, disk subdepressed with or without low umbo, warm brown, hazel brown (6E6–8), pale golden brown or orange-brown, all over covered with small, concolorous, fibrillose squamules or minute scales, dry, in young specimens with whitish, non-persisting fibrillose veil remnants at margin. Lamellae close, 36–48 reaching stipe, 3 (–7) lamellulae, adnate, broadly adnate or marginate-decurrent, up to 6 mm wide, at first greyish yellow (4B5), umber brown (6E6–8) to chocolate brown, with faint rust tinge, entire or subfimbriate edges paler; context whitish or greyish yellow (4B4–5), orange at frass holes and upon exposure. Stipe 10–35 × (3–) 4–8 mm, cylindrical, equal, concolorous with pileus, at base with white tomentum, strongly innate-fibrillose all over, apex not pruinose; cortina conspicuous, persistent, annulate, composed of whitish or pale cinnamon fibrils; towards base velar remnants as numerous woolly-fibrillose concolorous belts and scaly zones, dry; context solid becoming fistulose. Odor and taste not distinctive.

Basidiospores 8.5–10 × 4.5–5 μm, amygdaliform (in side view) or obovoid (in front view), pale yellow-brown, smooth, germ pore absent, brown in deposit. Basidia (25–) 30–38 × 6–7 μm, 4-spored (rarely 2-spored), cylindricalclavate, becoming necropigmented. Cheilocystidia 15–35 (–40) × 12–22 μm, conspicuous, broadly clavate or vesiculose, thin-walled, hyaline, crystals absent. Pleurocystidia absent. Caulocystidia absent. Pileipellis a trichoderm of erect, tightly fasciculate, cylindrical hyphae, 6–10 μm wide, terminal cells not differentiated, hyaline or yellowish, non-gelatinized wall, strongly encrusted with (yellow-) brown pigment; subpellis hyphae cylindrical, 8–14 μm wide, encrusted with yellow-brown pigment; oleiferous hyphae absent. Clamp connections present.

Habitat: Singly on lateritic soil in tropical submontane conifer forest (dominated by Pinus kesiya , P. merkusii ) and dipterocarp forest (dominated by Dipterocarpus obtusifolia ), 500–600 m elev.

Known distribution: Northwest Thailand (type), India (Kerala).

Other specimens examined: THAILAND. Hwy 1095, at 22 km marker, N19˚07.570‘, E98˚45.647‘, 4 Jun. 2006, leg. D.E. Desjardin (DED8022, SFSU; ZT13034) GenBank accession no. EU569844. Mae Hong Son Prov.: south of Mae Hong Son, Hwy. 108, at 235 km marker, road to TV Station 3–9, on lateritic soil (in recently burned) tropical submontane mixed broadleaf conifer forest (dominated by Dipterocarpus obtusifolia , Pinus kesiya ), 29 Jun. 2002, leg. E. & A. Horak (ZT10072) GenBank accession no. GQ892936.

Notes: Inocybe errata belongs to subgen. Mallocybe ( Mallocybe clade) and is affiliated with the I. dulcamara - complex that encompasses numerous closely related taxa. The occurrence and geographical distribution of I. errata is not only restricted to Thailand, but this distinctive species is also known from India (Kerala) in association with dipterocarps (ZT9238; EU569845). Inocybe errata is sister to an undescribed species from Zambia (PC 96204) and appears to have diverged from the African species relatively recently ( Matheny et al. 2009). Both are phylogenetically related to a Mediterranean species, I. heimii Bon.

Figures

PLATE 2. a. Inocybe latibulosa (DED8055, holotype). b. Inocybe neglecta (DED8063, holotype). c. Inocybe errata (ZT10108, holotype). d. Inocybe proxima (DED8007, holotype). Scale bars = 10 mm. Photos a, b, d, by Dennis Desjardin, c, by Egon Horak.

FIGURE 6. Macroscopic and anatomical features for Inocybe errata (ZT10108, holotype). a. Basidiomes. b. Basidiospores. c. Basidia. d. Cheilocystidia. e. Pileipellis. Scale bars: basidiomes = 20 mm, basidiospores = 10 μm, basidia and cystidia = 20 μm, pileipellis = 40 μm. Drawings by Egon Horak.