Inocybe griseorubida K. P. D. Latha & Manim., 2015

Deepna Latha, K. P. & Manimohan, Patinjareveettil, 2015, Inocybe griseorubida, a new species of Pseudosperma clade from tropical India, Phytotaxa 221 (2), pp. 166-174 : 168-171

Inocybe griseorubida K. P. D. Latha & Manim. , sp. nov. Figs. 1A–F ; Figs. 2A–F

MycoBank MB 812901

Etymology:—The specific epithet (Latin) refers to the grayish red pileus of this species.

Diagnosis:—This species is characterized by a grayish red pileus with a well-developed, grayish, sericeous velipellis; ellipsoid, oblong or subphaseoliform basidiospores (7–13 × 5–7 μm); versiform cheilocystidia often with a resinous substance towards the apex; an ecological association with Dipterocarpaceae ; and is phylogenetically distinguished from other species of Inocybe .

Holotype:— INDIA. Kerala State: Ernakulam District, Perumbavoor, Iringolkavu Sacred Grove , 31 July 2012, K. P. Deepna Latha, DKP8 ( CAL 1253 ).

Description:—Basidiomata small. Pileus 5–23 mm diam., almost parabolic when very young, becoming convex, finally plano-convex with a shallow central depression or occasionally with a small umbo surrounded by a slight depression; surface grayish red (12E4–5/OAC448) when very young, becoming grayish (12E4/OAC504) at the center, grayish red (12D3, 12D4/OAC505) elsewhere, appressed-fibrillose, radially rimose towards the margin; grayish, sericeous, well-developed velipellis observed in all collections, which covers the pileus surface and often dense at the center; margin initially incurved, becoming decurved to slightly reflexed with age, appendiculate when very young, becoming crenate or somewhat wavy, slightly fissile. Lamellae emarginate with a small decurrent tooth, moderately crowded, initially orange-gray (6B2/OAC669), becoming reddish gray (7B2/OAC599), up to 3 mm deep, with lamellulae of 3 lengths; edges crisped, whitish. Stipe 13–37 × 2.2–5 mm, central, terete, equal or slightly tapering towards the apex, cartilaginous, solid; surface reddish gray (12C2/OAC591) when very young, becoming grayish rose (12B3/OAC562), fading reddish white (12A2) towards the apex with age, with appressed as well as slightly recurved fibrils all over, more so towards the apex; base slightly enlarged, not bulbous, whitish. Context soft, up to 3 mm wide, off-white. Odor and taste not distinctive.

Basidiospores (7)8–12(13) × 5–6.5(7) (9.6±0.1.2 × 5.4±0.5) μm, Q = 1.2–2.2, Qm = 1.8, smooth, ellipsoid to slightly oblong or subphaseoliform or occasionally with a slight median constriction, slightly thick-walled, pale brown or pale yellowish brown. Basidia 20–47 × 6–17 μm, clavate, thin-walled, hyaline or pale yellow, 4-spored; sterigmata up to 6 μm long. Pleurocystidia absent. Lamella edge sterile or occasionally heterogeneous. Cheilocystidia 25–66 × 8– 19 μm, abundant, versiform: clavate, broadly clavate, cylindrical, cylindro-clavate, ovoid, oblong, narrowly fusiform, narrowly utriform or with a capitate or subcapitate apex, rarely septate, often coated with a resinous substance especially towards the apex, thin- to slightly thick-walled, hyaline, occasionally with tiny amorphous contents. Lamellar trama subregular; hyphae 3.5–10 μm wide, inflated up to 27 μm, thin-walled, hyaline or very pale yellow. Subhymenium inconspicuous. Pileus trama subregular; hyphae 4–20, thin-walled, hyaline or pale yellow. Pileipellis a disrupted cutis with supra- and subpellis regions; suprapellis composed of compact, closely septate, non-encrusted hyphae (elements 22–40 × 8–10 μm), with a pale violet plasmatic pigment; subpellis made up of both narrow and inflated, parallel hyphae (6–32 μm wide) with dense, brown or yellowish brown, external spiral encrusting pigment. Stipitipellis a cutis often disrupted with loose, entangled, superficial covering of hyphae especially towards the apex; hyphae 4–15 μm wide, thin- to slightly thick-walled, with a pale violet plasmatic pigment and faint hyaline encrustations, sometimes with yellowish brown amorphous contents. Caulocystidia absent. Oleiferous hyphae observed in all trama. Clamp connections present on all hyphae.

Habitat:— in small groups, on soil, near Vateria indica L. ( Dipterocarpaceae , broad-leaved) trees.

Geographical distribution range:—known only from the type locality in Kerala State, India.

Additional specimens examined:— INDIA. Kerala State: Ernakulam District, Perumbavoor, Iringolkavu Sacred Grove , 30 July 2012, K. P. Deepna Latha, DKP7 ( CAL 1254 ) ; 26 August 2014, K. P. Deepna Latha, DKP269 ( CAL 1255 ) .

Comments:—The authors could not find a species description in the literature that matches exactly with Inocybe griseorubida . Comparison of the ITS (678 bp), nLSU (870 bp) and rpb2 (761 bp) sequences derived from I. griseorubida with the nucleotide sequences of taxa available in GenBank indicate that the derived ITS, nLSU and rpb2 sequences of I. griseorubida are distinct. Based on BLASTn search using the ITS sequence, no close hit was obtained with an evalue of zero. An unnamed species, Inocybe sp. IND02 was the closest hit in BLASTn search for both nLSU (GenBank KP171060; Identities = 833/873 (95 %), Gaps = 10/873 (1 %)) and rpb2 (GenBank KM656098; Identities = 701/750 (93 %), Gaps = 2/750 (0 %)) sequences. Inocybe sp. IND02 is an undescribed species from Kerala, the details of which are not available for comparison.

Phylogenetic analysis generated a tree that showed the relative placement of I. griseorubida . The phylogeny was inferred from maximum likelihood (ML) analysis which is shown in Fig. 3 . The ML analysis of the rpb2 dataset placed I. griseorubida in the Pseudosperma clade with full ML bootstrap support (100% BS). In the Pseudosperma clade, I. griseorubida nested in the I. rimosa complex with significant ML bootsrap support (97% BS). Within this complex, I. griseorubida , Inocybe sp. IND02 and Inocybe sp. PBM2983 clustered together as a discrete clade. Within this clade, the present species, I. griseorubida formed a lineage distinct from other two taxa of that clade with high ML bootstrap support (98% BS).

Figures

FIGURE 1. A–F: Inocybe griseorubida (CAL 1253, holotype). A. Basidioma; B. Basidiospores; C. Basidium; D. Cheilocystidia; E. Pileipellis; F. Stipitipellis. Scale bars: A=10 mm; B–F=10 μm. Photos: By K.P.D. Latha.

FIGURE 2. A–F: Inocybe griseorubida (CAL 1253, holotype). A. Basidioma; B. Basidiospores; C. Basidium; D. Cheilocystidia; E. Pileipellis; F. Stipitipellis. Scale bars: A=10 mm; B–F=10 μm. Drawings: By K.P.D. Latha.

FIGURE 3. ML tree of rpb2 sequences showing the placement of I. griseorubida within the Pseudosperma clade. Values above or below branches indicate bootstrap proportions. BS values ≥50% are shown. GenBank accession numbers are given after the name of each taxon.