Clitopilus orientalis T.J. Baroni & Watling, Mycotaxon, 1999

Anil Raj, K. N. & Manimohan, Patinjareveettil, 2018, A new species and a new record of Clitopilus and a description of C. orientalis from India based on morphology and molecular phylogeny, Phytotaxa 343 (1), pp. 47-59 : 52-55

Clitopilus orientalis T.J. Baroni & Watling, Mycotaxon 72: 58 (1999). Figs. 3. A–G

Description:— Basidiocarps small, omphalinoid to clitocyboid. Pileus 6–33 mm diam., convex with or without a shallow central depression when young, becoming depressed to deeply concave or rarely somewhat plano-convex or applanate with age; surface pure white, weakly hygrophanous and becoming somewhat whitish, not striate, glabrous to the naked eye, velutinous under a lens, tacky when wet, with fine longitudinal ridges towards the margin when young that become more pronounced with age; margin almost inrolled when young, becoming incurved to somewhat straight at maturity, with 1–2 rows of marginal scales. Lamellae subdecurrent to deeply decurrent, rarely furcate, close, initially white, becoming orange-white (6A2/OAC759) at maturity, up to 4 mm wide, with lamellulae of 1–6 lengths; edge entire to the naked eye, finely torn under a lens, concolorous with the sides. Stipe 12–31 × 1–7 mm, central or rarely eccentric, terete, equal or slightly tapering towards the apex, cartilaginous, solid; surface white or whitish, finely appressed-fibrillose all over, finely pruinose towards the apex; base with mycelial cords. Odor not distinctive. Taste farinaceous. Spore print not obtained.

Basidiospores 5–8(8.5) × 3.5–6.5 (6.43 ± 0.72 × 4.25 ± 0.43) μm, Q = 1–2, Qm = 1.46, ellipsoid, with 6–10 longitudinal ribs, colorless, thin-walled. Basidia 17–27 × 6–9 μm, clavate, colorless or pale yellow, thin-walled, 4- spored; sterigmata up to 4 μm long. Lamella-edge heteromorphous or rarely fertile. Cheilocystidia 15–78 × 4–6.5 μm, scattered, cylindrical, often tapering towards the apex, flexuose or narrowly clavate, often septate, colorless, thin-walled. Pleurocystidia absent. Lamellar trama subregular; hyphae 2.5–13 μm wide, colorless, thin-walled. Subhymenium inconspicuous. Pileus trama subregular; hyphae 2–8 μm wide, colorless or pale yellow, thin-walled. Pileipellis a cutis occasionally disrupted by erect solitary hyphae; hyphae loosely arranged, slightly gelatinized, 3–7.5 μm wide, colorless, thin-walled. Stipitipellis a cutis often disrupted by bunches of ascending hyphae towards the stipe apex; hyphae 2–5.5 μm wide, thin-walled, colorless or very pale yellow; terminal cells cystidioid, 14–40.5 × 3.5–7 μm, flexuose-cylindric, narrowly clavate or narrowly utriform, thin-walled. Caulocystidia absent. Clamp connections absent.

Habitat: — On soil, scattered or in small groups, among moss or crevices of lateritic stones. August–November.

Worldwide geographical distribution range:—Known from Malaysia (Type) and India.

Specimens examined:— INDIA. Kerala State: Kozhikode District, Vadakara , Vellyapilly : 5 August 2011, K. N. Anil Raj AR785 ( CAL 1613 ) ; 20 August 2011, K. N. Anil Raj AR835 ( CAL 1614 ) ; 7 November 2011, K. N. Anil Raj AR933 ( CAL 1615 ) ; Ernakulam District, Iringolkavu Sacred Grove : 13 August 2013, K. P. Deepna Latha DKP121 ( CAL 1616 ). GenBank accessions: MG345134 ( ITS), MG321558 (nLSU) and MG321559 (rpb2) .

Comments:—The Kerala collections agree with Clitopilus orientalis , originally described from Malaysia ( Baroni & Watling 1999), in almost all characters. The only difference observed was the slightly gelatinized pileipellis in our collections. Clitopilus orientalis is characterized by a white pileus with a glabrous or slightly matted, silky-fibrillose surface, a radially ridged or fluted, incurved pileal margin, subdecurrent to deeply decurrent lamellae with concolorous edges, ellipsoid or short-ellipsoid basidiospores, widely scattered, cylindrical or ventricose-rostrate cheilocystidia and a pileipellis and stipitipellis with ascendant or erect, cylindric, colorless end cells. Clitopilus orientalis can be placed in the section Scyphoides ( Singer 1986) owing to their small basidiocarps, basidiospores that are smaller than 10 μm and the presence of a constant and distinct stipe.

A BLASTn search of the GenBank using the ITS (426 bp) and nLSU (822 bp) sequences obtained from the present collection showed no close hits with zero e-value. In a BLASTn search using the rpb2 sequence (666 bp), the closest hits were Clitopilus crispus (KC816911, 99% identity) and C. apalus (KC816906, 99% identity).

Figures

FIGURE 3. A–G: Clitopilus orientalis (CAL 1616 & CAL 1613). A–B. Basidiocarps; C. Basidiospores; D. Basidium; E. Pileipellis; F. Cheilocystidia; G. Stipitipellis. Scale bars: A–B = 1 cm; C–G = 10 μm. Photos: By K.N.A. Raj.