Candolleomyces albosquamosus P.K. Nayana & C.K. Pradeep, 2023

Nayana, P. K. & Ck, Pradeep, 2023, A new species of Candolleomyces (Psathyrellaceae, Agaricales) from Western Ghats, India, Phytotaxa 606 (1), pp. 63-72 : 66-69

Candolleomyces albosquamosus P.K. Nayana & C.K. Pradeep sp.nov. ( Figs. 1 , 2 )

MycoBank: MB849111

Diagnosis:—It can be distinguished from the closely related Candolleomyces thailandensis by the small, pale ellipsoid to elongate basidiospores (6–6.4 × 3.6–4 µm) with an indistinct germ pore, polymorphic cheilocystidia and caulocystidia, lignicolous habitat, and a distinctive nrITS sequence.

Holotype:— INDIA. Kerala State: Thiruvananthapuram district, Palode , JNTBGRI campus, 8.75°N, 77.02°E, elev. 150 m, 16 June 2021, Nayana TBGT (M)18600!. GenBank: OQ676550 ( ITS).

Etymology:— albosquamosus , refers to the white floccose velar squamules on the pileus

Description:—Basidiomata small, up to 58 mm high, thin, fragile. Pileus 12.0– 38.5 mm diam., parabolic in buds, becoming hemispherical, campanulate, convex to broadly convex at maturity; surface honey yellow (5D6), light brown (5D4, 5D5), yellowish brown (5C5), mustard brown (5E6) finally brownish gray/brownish beige (6D 2,6E 3) with age, paler at margin, strongly hygrophanous, with white, minute floccose, evanescent velar squamules scattered throughout, pellucid striate up to the disc, dry, micaceous; margin straight, irregular, appendiculate. Lamellae adnexed, yellowish white in buds becoming brownish gray to brown (4A2,4C2,6C2,6D 3,6E 4,7E 4) when mature, up to 3.5 mm wide, crowded with lamellulae of 3–4 lengths; edge concolorous to the sides, minutely fimbriate. Stipe 11–57 × 1.5–4.0 mm, central, cylindric, equal or slightly tapering upward, slightly compressed towards the base in some specimens, curved, hollow, brittle; surface white, pruinose at apex, floccose to squamulose in the lower half; base with white strigose hairs and white mycelial mat. Context thin, concolorous to pileus, up to 1 mm, soft, brittle. Odor mild. Spore sprint brown (7E4).

Basidiospores 6.0–6.4 × 3.6–4.0 µm (avL = 6.16 µm, avW = 3.86 µm), Q = 1.5–1.7 (Qm = 1.575), ellipsoid to elongate, grayish orange in water, nearly hyaline in 3% aqueous KOH, thick-walled, smooth, with an indistinct germ pore and minute hilar appendix. Basidia 14–20 × 6.0–7.2 µm, clavate, 4-spored, thin-walled, hyaline. Lamella edge sterile with cheilocystidia and paracystidia. Cheilocystidia crowded, abundant, 24.0–36.8 × 12–18 µm, polymorphic, clavate, utriform to broadly utriform, oblong, rarely lageniform with obtuse apex, rarely capitate, thin-walled, hyaline. Paracystidia abundant, 12–20 × 8–12 µm, globose, subglobose to clavate, thin-walled, hyaline. Pleurocystidia absent. Hymenophoral trama regular, hyphae 2–46 µm broad, inflated, thin-walled, hyaline, encrusted, slightly constricted at septa. Subhymenium pseudoparenchymatous. Pileal trama composed of thin-walled, hyaline, branched, encrusted, inflated, 2–38 µm broad hyphae constricted at septa. Pileipellis a 2–3 layered epithelium composed of globose to subglobose cells, 21.2–50.0 × 15.2–46.0 µm, thin-walled, hyaline. Stipitipellis composed of thin-walled, hyaline, 4–24 µm broad encrusted hyphae. Stipe with caulocystidia at the apex along with paracystidia. Caulocystidia scattered in groups, abundant, 19.2–54.0 × 8–16 µm, polymorphic, flexuous, lageniform, utriform, broadly utriform with obtuse, rarely rostrate to capitate apex, thin-walled, hyaline. Paracystidia scattered, moderately abundant, 10–24 × 8–12 µm, subglobose to clavate, thin-walled, hyaline. Velar squamules composed of thin-walled, hyaline, branched, encrusted, 2.8–20.0 µm broad hyphae. Clamp connections and oleiferous hyphae present in all tissues.

Habit, habitat and phenology:— Solitary, paired, scattered, rarely caespitose, usually on dead bamboo culms, sticks and rarely on angiosperm twigs in tropical forest, Kerala State, India. June–December.

Additional specimens examined:— India, Kerala State, Thiruvananthapuram district, Palode , JNTBGRI campus: 5 August 2020, Nayana TBGT (M) 18234; ibid., 8 September , 2020 Nayana TBGT (M) 18277; ibid., 15 September 2020, Nayana TBGT (M) 18296; ibid., 23 September 2020, Nayana TBGT (M) 18334; ibid., 24 September 2020, Nayana TBGT (M) 18340; ibid., 27 September 2020, Nayana TBGT (M) 18347; ibid., 27 September 2020, Nayana TBGT (M) 18353; ibid., 18 October 2020, Nayana TBGT (M) 18424; ibid., 20 November 2020, Nayana TBGT (M) 18431; ibid., 9 December 2020, Nayana TBGT (M) 18444; ibid., 10 December 2020, Nayana TBGT (M) 18448; ibid., 8 June 2021, Nayana TBGT (M) 18590; ibid., 12 June 2021, Nayana TBGT (M) 18595; ibid., 21 June 2021, Nayana TBGT (M) 18605; ibid., 29 June 2021, Nayana TBGT (M) 18612; ibid., 14 July 2021, Nayana TBGT (M) 18617; ibid., 20 July 2021, Nayana TBGT (M) 18623; ibid., 23 August 2021, Nayana TBGT (M) 18625; ibid., 27 August 2021, Nayana TBGT (M) 18628; ibid., 7 September 2021, Nayana TBGT (M) 18669; ibid., 9 September 2021, Nayana TBGT (M) 18675; ibid., 15 September 2021, Nayana TBGT (M) 18686; ibid 2 November 2021, Nayana TBGT (M) 18739; ibid., 5 July 2022, Nayana TBGT (M) 18891; ibid., 6 July 2022, Nayana TBGT (M) 18892; ibid., 8 July 2022, Nayana TBGT (M) 18895; 5 July 2022, Nayana TBGT (M) 18949.

Figures

FIGURE 1. Candolleomyces albosquamosus (TBGT(M)18600, holotype).A–H. Habit in situ; I –J. Basidiomata with immature to mature lamellae. Scale bar = 10 mm. Photos: P.K. Nayana

FIGURE 2. Candolleomyces albosquamosus (TBGT(M)18600, holotype). A. Basidia; B. Basidiospores; C. Cheilocystidia; D. Caulocystidia; E. Pileipellis; F. Veil elementsScale bar: A–B = 10 µm; C–F = 20 µm. Photos by: P.K. Nayana