Candolleomyces niveosquamosus P. K. Nayana & C. K. Pradeep, sp.nov.
Creators: name: Nayana, P. K.
name: Pradeep, C. K.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Psathyrellaceae
Candolleomyces
Candolleomyces niveosquamosus

description: Candolleomyces niveosquamosus P.K. Nayana & C.K. Pradeep sp.nov. (Figs. 2, 3)
MycoBank: MB854240
Diagnosis:—Differs from the closely related C. albosquamosus by slightly larger grayish brown pileus with dark brown disc (17.5–50 mm), larger (6.8–8.0 × 4.0–4.4 µm), brown basidiospores with a distinct germ pore and habitat.
Holotype:— INDIA. Kerala State: Thiruvananthapuram District. Palode, JNTBGRI campus, 8.75°N, 77.02°E, elev. 150 m, 07 April 2022, Nayana TBGT (M)18773!. GenBank: PP741631 (ITS); PP741635 (LSU).
Etymology:— niveosquamosus, refers to the white floccose velar squamules on the pileus.
Description:—Basidiomata small to medium sized, thin. Pileus 17.5–50 mm diam., convex, plano-convex, applanate to uplifted with a small obtuse umbo at centre; surface grayish orange (5B3), brownish gray (6C2) with a brown (6E4) to dark brown (6F5/6F6/7F5) disc, hygrophanous, with white evanescent floccose velar squamules dense at the centre, scattered towards the margin, pellucid striate, slightly wrinkled on drying, dry; margin straight, strongly appendiculate, incised. Lamellae adnexed, grayish brown (6D3), brown (6E4/7E4) to dark brown (6F4/6F56F7/7F7), up to 4 mm broad, close to crowded with lamellulae of 3–4 lengths; edge concolorous to the sides, fimbriate. Stipe 27–95 × 2–5 mm, central, cylindric, slightly tapering upward, curved, hollow, brittle; surface white, pruinose at the apex, covered with white fibrils or floccose velar squamules towards base; base with white strigose hairs. Context concolorous to the pileus, 1 mm broad, soft. Odor mild, not distinct. Spore print dark brown (8F4).
Basidiospores 6.8–8.0 × 4.0–4.4 µm (avL= 7.38 µm, avW= 4.06 µm), Q= 1.63–2.0 (Qm = 1.67), ellipsoid to elongate, light brown in water, grayish brown in 3% aqueous KOH, thick-walled, smooth, with a large germ pore and minute hilar appendix. Basidia 14.4–16.7 × 6.6–8.8 µm, clavate, 4-spored, thin-walled, hyaline. Lamella edge sterile with cheilocystidia and paracystidia. Cheilocystidia in groups or scattered, abundant, 24.9–34.1 × 10.1–16.8 µm, utriform, cylindrical, ellipsoid, rarely bifurcate, thin-walled, hyaline. Paracystidia moderately abundant, 13.2–21.6 × 11.6–19.4 µm, globose to subglobose, thin-walled, hyaline. Pleurocystidia absent. Hymenophoral trama regular, hyphae 2.5–16.7 µm wide, thin-walled, hyaline. Subhymenium pseudoparenchymatous. Pileal trama composed of thin-walled, hyaline, encrusted, inflated, 3.7–34.6 µm wide hyphae constricted at septa. Subcuticular hyphae brown in KOH. Pileipellis an epithelium, composed of globose to subglobose elements, 16.4–32.7 × 17.5–31.5 µm, thin-walled, hyaline. Veil made up of thin-walled, hyaline, branched, 6.6–18.9 µm wide hyphae. Stipitipellis a cutis, composed of thin-walled, hyaline, 3.70–29.81 µm broad, encrusted hyphae. Stipe apex with caulocystidia along with paracystidia. Caulocystidia moderately abundant, in groups or scattered, 23.7–55.1 × 11.3–13.7 µm, lageniform, utriform, cylindrical with obtuse or capitate apex, slightly thick-walled, hyaline. Paracystidia scattered, moderately abundant, 12.6–16.3 × 8.8–9.4 µm, globose to subglobose, thin-walled, and hyaline. Clamp connections common in all tissues.
Habit, Habitat and phenology:—Solitary, scattered to gregarious on sandy soil or on decayed angiosperm wood in tropical forest, Kerala State, India. This species fruits from March–May.
Additional specimens examined:— India, Kerala State: Thiruvananthapuram District, Palode, JNTBGRI campus: 22 April 2022, Nayana 18799; ibid., 19 May 2022, Nayana TBGT (M)18824; ibid., 30 March 2023, Nayana TBGT (M)19023; ibid., 11 April 2023, Nayana TBGT (M)19046; 25 April 2023, Nayana TBGT (M)19068.
Notes:—Climatic geolocation, umbonate pileus with white evanescent floccose velar squamules, appendiculate pileal margin, brown ellipsoid to elongate basidiospores with a distinct germ pore, sterile lamella edge with abundant cylindrical to utriform cheilocystidia, moderately abundant cylindrical, lageniform to utriform caulocystidia, and small to medium-sized basidiomata are the characteristics of C. niveosquamosus.
A BLASTn search using the nrITS sequence generated from the present collections, TBGT(M)18773 (662 bp) and TBGT(M)19023 (631 bp), revealed a 98% sequence similarity with Candolleomyces cladii-marisci (Sicoli, N.G. Passal., De Giuseppe, Palermo, Pellegrino, D. Deschuyteneer & Voto) N.G. Passal. & Sicoli (2023:1) from Italy (MK080112). Candolleomyces cladii-marisci, initially described from Italy, is macroscopically similar to the Indian material; however, it is distinct in having a slightly smaller pileus (10–35 mm), larger basidiospores (7.2–11.8 × 4.3–6.0 µm) and slightly larger (21.5–54 × 6.0–11 µm) cheilocystidia.A pairwise comparison of the nrITS sequence of the new species with C. cladii-marisci showed 12 base pair differences. The new taxon is also related to other recently described species viz., C. albosquamosus P.K. Nayana & C.K. Pradeep and Candolleomyces thailandensis Suwannar., Kumla & Lumyong (2022: 431). The smaller honey yellow to brownish gray pileus (12.0– 38.5 mm), smaller, pale basidiospores (6.0–6.4 × 3.6–4.0 µm) with an indistinct germ pore and lignicolous habitat are the distinguishing features of C. albosquamosus. A pairwise comparison of the nrITS sequences of C. albosquamosus with the new taxon exhibits 12 base pair differences. Candolleomyces thailandensis also shares a close morphological and molecular relationship with the present taxon, however, it differs in its smaller pileus (12–25 mm) and smaller (5.5–7.5 × 3.5–4.5 µm) basidiospores and molecularly by 24 base pair differences in the nrITS region.
Other morphologically and molecularly related species include C. yanshanensis C.L. Hou & Hao Zhou (2022: 114), C. subcandolleanus C.L. Hou & Hao Zhou (2022: 115), C. incanus C.L. Hou & Hao Zhou (2022: 117), C. bivelatus (Contu) D. Wächt. & A. Melzer (2020: 1232), C. candolleanus (Fr.) D. Wächt. & A. Melzer (2020: 1233), C. trinitatensis (R.E.D. Baker & W.T. Dale) D. Wächt. & A. Melzer (2020: 1234), C. badiophyllus (Romagn.) D. Wächt. & A. Melzer (2020: 1231) and C. badhyzensis (Kalamees) D. Wächt. & A. Melzer. (2020: 1231). Candolleomyces yanshanensis, originally reported from China is distinct by its slightly larger pileus (20–60 mm) and larger basidiospores (5.8–8.2 × 3.3–5.4 µm). The Chinese species C. subcandolleanus and C. incanus are distinct by their smaller pileus (5.0– 20 mm; 5.0– 25 mm), and smaller basidiospores (5.5–6.7× 3.2–4.5 µm; 6.0–7.0 × 3.2–4.5 µm) lacking a germ pore (Zhou et al. 2022). Larger basidiospores (9–9.5 × 5–5.5 µm), the presence of 2-spored basidia, and herbaceous habitat distinguish C. bivelatus from the present species (Voto et al. 2019). Candolleomyces candolleanus can be distinguished by its slightly larger pileus (3–7 cm), and slightly larger basidiospores (7–9 × 4–5 µm) (Smith 1972; Kits van Waveren 1985; Pegler 1986). Candolleomyces trinitatensis is distinct in its slightly smaller pileus (15–20 mm) and larger basidiospores (7–10 × 3.5– 5 µm) (Baker & Dale 1951). Candolleomyces badiophyllus and C. badhyzensis can be distinguished by their notably larger (11–13.2 × 5.7–6.2 µm; 10.2–11.5 × 5.5–6.5 µm) basidiospores (Kalamees 1981; Romagnesi 1952).
description: Published as part of Nayana, P. K. & Pradeep, C. K., 2024, Morphological and phylogenetic analyses reveal two new species of Candolleomyces (Psathyrellaceae) from India, pp. 255-267 in Phytotaxa 659 (3) on pages 259-261, DOI: 10.11646/phytotaxa.659.3.3, http://zenodo.org/record/13217942