Calocybella babruka K. P. D. Latha & Manim., 2016

Deepna Latha, K. P., Anil Raj, K. N., Cherolil, Thushara, Sharafudheen, Shahina A. & Manimohan, Patinjareveettil, 2016, Three new species of Calocybella from India based on morphology and molecular phylogeny, Phytotaxa 255 (2), pp. 133-143 : 137-138

Calocybella babruka K. P. D. Latha & Manim. , sp. nov. Figs. 1D–E , 3A–G

MycoBank MB 815577

Etymology:— babruka (Sanskrit) , brownish; refers to the overall brownish color of the basidiomata of this species.

Diagnosis:—Differing from Calocybella pudica in having a brown pileus with a granulose surface and a lobate margin, emarginate lamellae with small decurrent teeth, a brown stipe with a whitish base, a context not discoloring on bruising, acynophilous basidiospores, occasional presence of crassobasidia, stipitipellis hyphae embedded in a resinous material and a distinctive ITS sequence (KU366466).

Holotype:— INDIA. Kerala State: Malappuram District, Calicut University Campus , 20 June 2015, K. P. Deepna Latha, DKP343 ( CAL 1289 ).

Description:— Basidiomata small, slenderly tricholomatoid. Pileus 10–25 mm diam., convex or hemispherical when young, becoming campanulate and finally plano-convex with a small indistinct umbo; surface initially reddish brown (9E4/OAC524) except at the margin which is brownish gray (9B2/OAC584), becoming brown (7E5/OAC538) or light brown (7D5/OAC558) all over at maturity, not striate, somewhat granulose all over; margin initially incurved, becoming decurved to somewhat straight with age, slightly wavy or somewhat lobate. Lamellae emarginate with a small decurrent tooth, moderately crowded, initially grayish orange (5B3/OAC717), becoming brownish orange (6C3/OAC661) at maturity, up to 3 mm wide, with lamellulae of 3–6 lengths; edge finely torn, concolorous with the sides. Stipe 18–30 × 3–4 mm, central, terete or slightly compressed, equal or slightly tapering towards the base, stuffed; surface brown (6E4/OAC640), appressed-fibrillose all over; base slightly enlarged, whitish. Context up to 2 mm thick at the center of the pileus, orange white (5A2/OAC683). Odor and taste not distinctive.

Basidiospores 4.5–6 × 3–4 (5 ± 0.39 × 3.15 ± 0.29) μm, Q = 1.43–1.83, Qm = 1.59, ellipsoid to oblong-ellipsoid, with a fine verrucose ornamentation, hyaline, thin- to slightly thick-walled, acyanophilous, inamyloid. Basidia 22–28 × 6–8 μm, clavate or rarely pedicellate-clavate, hyaline, thin-walled, siderophilous, 4-spored; sterigmata up to 2 μm long. Crassobasidia occasional. Lamella-edge fertile. Pleuro- and cheilocystidia absent. Lamellar trama subregular to almost regular; hyphae 3–16 μm wide, hyaline, thin-walled, not discoloring in KOH, inamyloid. Pileus trama interwoven; hyphae 2–12 μm wide, with a pale yellowish brown wall pigment which is darker towards the pileipellis, thin-walled, not discoloring in KOH, inamyloid. Pileipellis a cutis; hyphae 3–9 μm wide, with a pale yellowish brown wall pigment, thin-walled, slightly gelatinized. Stipitipellis a cutis composed of narrow, interwoven hyphae coated with a resinous material; hyphae 2–7 μm wide, with a pale yellowish brown wall pigment which is paler towards the stipe base, thin-walled. Caulocystidia absent. Clamp connections observed on all hyphae.

Habitat:— scattered or in small groups, on the ground.

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

Comments:— Calocybella babruka seems to be somewhat close to C. pudica in having a similar looking pileus, somewhat similarly-colored, moderately crowded lamellae, a fibrillose stipe with a tapered base, inamyloid basidiospores of somewhat similar size, shape and ornamentation, siderophilous basidia, lamellae devoid of both pleuro- and cheilocystidia, slightly gelatinized hyphae of the pileipellis, a stipitipellis lacking caulocystidia, and clamped hyphae. However, C. pudica has an orange to brownish orange pileus, emarginate lamellae lacking a decurrent tooth, a pale yellow stipe, cyanophilous basidiospores, occasional presence of 2-spored basidia, hyphae of the stipitipellis lacking a resinous coating, and a mealy odor ( Vizzini et al. 2015). Calocybella lohitha differs from C. babruka in having reddish basidiomata, sinuate lamellae, an apically tapered stipe, reddish brown or maroon plasmatic pigment in hyphae of the pileus trama, and stipitipellis hyphae not embedded in a resinous material. Also, a pairwise alignment of the ITS sequences of these two species exhibited only 85% identity. Calocybella swetha differs in having whitish basidiomata, smooth basidiospores, a trichoderm-type pileipellis and stipitipellis hyphae devoid of resinous coating. In addition, C. babruka (KU366466) and C. swetha (KU366467) showed only 87% identity in a pair wise alignment of their ITS sequences).

In a megablast search using the ITS sequence of C. babruka (KU366466: 679 bp), Lyophyllaceae sp. MEL 2382862 (KP012736) was the closest hit with 88% sequence identity (98% query cover) followed by C. pudica (KP858000) with 89% sequence identity (95% query cover). Lyophyllaceae sp. MEL 2382862 is a collection from Australia, however, the details of which are unavailable for comparison.

Figures

FIGURE 1. A–F: Basidiomata of the three new species of Calocybella. A–C. C. lohitha. D–E. C. babruka. F–G. C. swetha. Scale bars: A–G = 10 mm. Photos: A–E. By K.P.D. Latha; F–G. By K.N.A. Raj.

FIGURE 3. A–G: Calocybella babruka (CAL 1289, holotype). A. Basidiospores; B. Basidiospore under SEM showing very fine warts (arrows); C. Crassobasidium; D. Siderophilous basidium; E. Stipitipellis; F. Hyphal septum showing clamp connection; G. Pileipellis. Scale bars: A, C–G = 10 μm; B = 1 μm.