Crepidotus volubilis C.K. Pradeep & A.M. Kumar, 2018

Kumar, A. Manoj, Vrinda, K. B. & Pradeep, C. K., 2018, Two new species of Crepidotus (Basidiomycota, Agaricales) from peninsular India, Phytotaxa 372 (1), pp. 67-78 : 71-72

Crepidotus volubilis C.K. Pradeep & A.M. Kumar sp. nov. Fig.2 , 3

MycoBank MB: 827756

Etymology:— “volubilis ” (Latin), refers to the coiled pileal structures of pileipellis.

Diagnosis:—This species is distinct on account of the white to orange-white densely pubescent pileus, the subglobose to ellipsoid verrucose basidiospores 5.5–7 (–8) × (4–) 4.5–6.5 μm, the clavate to cylindro-clavate cheilocystidia, the pileipellis as an interrupted epicutis and the presence of clamp connections.

Holotype:— INDIA. Kerala State: Thiruvananthapuram district, Palode, JNTBGRI campus, 14 May 2015, Manoj TBGT15648 ( CAL 1679 !). GenBank accessions: MH845231 (nrITS); MH310742 (nrLSU).

Description:— Basidiomata small, sessile, laterally attached. Pileus 3–18 mm diam., convex to slightly applanate, dimidate, spathuliform, reniform, orbicular to mostly flabelliform; surface white to off white becoming pale yellow to orange-white (3A3/4A2/4A3/4A4/5A2) densely pubescent, more prominent towards the base, pellucid-striate nearly up to the base from the margin, slightly hygrophanous, moist when fresh, soon dry; margin straight to slightly upturned, wavy in mature basidiomata, entire, rarely incised. Lamellae radiating from a lateral point or sometimes from a reduced stipe, adnexed, white to grayish orange (3A3/4A2/4A3/4A4/5A2/5B3/6A2), ventricose, up to 2 mm deep, close with lamellulae of 2–5 lengths; edge concolorous with faces, entire, exceeding the margin. Stipe absent or reduced. Context thin, pale. White mycelial mat present at the base. Odor not distinctive. Spore print clay to raw sienna (5D5/5D8/6C6/6D6/6D5/6D7).

Basidiospores 5.5–7 (–8) × (4–) 4.5–6.5 μm (Lm = 6.36 ± 0.66, Wm = 5.16 ± 0.60); Q= 1.12–1.42; Qm= 1.23, subglobose to ellipsoid, pale yellow in KOH, moderately thick-walled, finely verrucose. Basidia 19–22.5 (–28) × 7 (–8) μm, clavate, 2- or 4-spored, thin-walled, hyaline. Lamella edge sterile with crowded cheilocystidia. Cheilocystidia 22–50 × 5.6–8 μm, clavate, cylindro-clavate, thin-walled, hyaline. Pleurocystidia absent. Hymenophoral trama regular, hyphae 6.4–11μm wide, thin-walled. Subhymenium pseudoparenchymatous. Pileus trama composed of thin-walled hyphae, 4–11 μm, hyaline. Pileipellis an epicutis interrupted with curved to coiled pileal elements, 32–45 × 5.6– 6.4 μm, cylindrical, clavate, curved to coiled, thin-walled, incrusted. Pileipellis hyphae 4.8–7 μm wide, thin-walled, hyaline, incrusted. Clamp connections present in all tissues. Oleiferous hyphae not observed.

Habitat:—Lignicolous, scattered to mostly gregarious on decaying twigs, branches and dead wood of angiosperm trees.

Additional specimens examined:— INDIA. Kerala State: Thiruvananthapuram district, Palode , JNTBGRI campus, 11 May 2014, Manoj TBGT15031 ; 31 October 2014, Manoj TBGT15511 ; 26 Apr 2015, Manoj TBGT15565 ; 29 April 2015, Manoj TBGT15586 ; 30 April 2015, Manoj TBGT15597 ; 12 May 2015, Manoj TBGT15633 ; 18 June 2015, Manoj TBGT15697 ; 1 July 2015, Manoj TBGT15740 ; 23 August 2015, Manoj TBGT15792 ; 29 September 2015, Manoj TBGT15869 ; 12 May 2016, Manoj TBGT16104 ; 25 August 2017, Manoj TBGT17049 ; 10 October 2017, Manoj TBGT17138 ; Palakkad district, Dhoni 31, October 2014, Manoj TBGT15511 , Thrissur district , Peechi , 10 June 2017, Manoj TBGT16836 .

Comments:— Crepidotus volubilis belongs to sect. Echinospori subsect. Porpophorini Singer (1947:94) due to its verrucose basidiospores and presence of abundant clamp connections ( Singer 1973). The authors could not find a species description that matches exactly with C.volubilis in any of the available literature ( Singer 1973; Hesler & Smith 1965; Senn-Irlet 1995; Hausknecht & Greilhuber 2010). Crepidotus volubilis can be compared to species such as Crepidotus palmarum Singer (1951: 406) , C. cesatii (Rabenh.) Sacc. (1877: 2) , C. circinatus Hesler & A.H. Sm. (1965: 133) and C. regularis Hesler & A.H. Sm. (1965: 114) . Crepidotus palmarum described from Brazil ( Singer 1973; Bandala & Montoya 2000) is similar in basidiomata size, colour, surface features and size and shape of basidiospores. Nevertheless, C. palmarum is quite distinct in having clavate-capitate cheilocystidia, a pileipellis as an undifferentiated epicutis and its apparent association with palms. Crepidotus cesatii ( Senn-Irlet 1995) is differentiated by its pure white, villose pileus, large [7–9 (–10) × 5.5–7 (–7.5) μm] broadly ellipsoid basidiospores and contorted forked antler-like cheilocystidia and cuticular pileipellis. Crepidotus circinatus is another analogous species characterized and distinctive by a small yellowish buff villose pileus, and fusoid clavate bottle-shaped cheilocystidia with forked/branched apices. Crepidotus regularis which is very similar to C. circinatus differs by a white fibrillose pileus, ellipsoid to ovoid basidiospores (6–8 × 4–5 μm) and forked ventricose cheilocystidia.

Comparison of the nrLSU sequence (946 bp) derived from Crepidotus volubilis with the nucleotide sequences of Crepidotus taxa available in GenBank indicate that the nrLSU sequence of C.volubilis is distinct. In the BLASTn search, the closest hit was Crepidotus thermophilus (AF205669) followed by Crepidotus caspari Velen. (1926: 70) [= Crepidotus amygdalosporus (AF205675)] with 96% sequence similarity. Crepidotus thermophilus , originally described from Florida, USA is distinct on account of its centrally stipitate basidiomes, inflated cheilocystidia and larger ellipsoid basidiospores (7–10.5 × 4–6 μm). Crepidotus caspari can be distinguished by its broadly lageniform cheilocystidia and relatively large basidiospores (8–9 × 5–6 μm). In the phylotree C.volubilis nested close to C.cinnabarinus ( Hesler & Smith 1965) which can be easily separated on account of its scarlet cinnabar red basidioma and absence of clamp connections. Moreover, C.cinnabarinus belongs to subsect. Aporpini Sing. (1947:94) of sect. Echinospori .

Figures

FIGURE 2. Crepidotus volubilis (CAL 1679, holotype). A–C. Habit in situ. Scale bar = 10 mm. Photos: By Manoj Kumar.

FIGURE 3. Crepidotus volubilis (CAL 1679, holotype). A. Basidia. B. Spores. C–D. Cheilocystidia. E. Pileipellis. F. Pileal elements. Scale bar = 10 μm. Photos: By Manoj Kumar.