Chlorophyllum tenue E.Falcão, Ferretti-Cisn., Silva-Filho, Koroiva & Wartchow, 2025

Falcão, Erica S., Ferretti-Cisneros, Nathalia U., Silva-Filho, Alexandre G. S., Koroiva, Ricardo & Wartchow, Felipe, 2025, Chlorophyllum tenue sp. nov. (Agaricaceae, Basidiomycota) from the Brazilian Caatinga semiarid region, European Journal of Taxonomy 976, pp. 182-193 : 185-189

Chlorophyllum tenue E.Falcão, Ferretti-Cisn., Silva-Filho, Koroiva & Wartchow sp. nov.

MycoBank MB 855028

Figs 2–4

Diagnosis

The species is characterized by the delicate basidiome, light brown to pinkish beige furfuraceous squamules on a light gray to dark cream brown background, cylindrical and slightly radicant stipe, ellipsoid basidiospores 8.7–9.7(–10.7) × 5.6–6.6 µm, 4-spored basidia, slender clavate-subcapitate cheilocystidia, and pileus covering elements varying from broadly clavate, clavate to slender clavate sinuous.

Etymology

From the Latin adjective tenuis, e = slender, thin, delicate, due to the slender basidiome of the new species.

Type material

Holotype

BRAZIL – Paraíba • São José dos Cordeiros; “ RPPN Fazenda Almas” [Private Reserve of Natural Patrimony Fazenda Almas ]; 7°28′45″ S, 36°54′18″ W; 26 Feb. 2019; A.G.S. Silva-Filho AGS 09-2019; solitary on soil among litter in vegetation of Caatinga Biome; JPB [66971] .

Description

Basidiome small, slender, lepiotoid. Pileus 42 mm plane-umbonate, surface squamulose, with a distinct reddish brown (OAC 733) umbo breaking up into small appressed scales, light brown (OAC 688) to rosy beige (OAC 689) irregularly shaped, radially oriented, scattered and detersile toward the margin; surface/background light grayish brown to dark cream (OAC 722, 718); margin striated; surface more densely packed toward central disk; context very thin, fragile. Lamellae free, white (OAC 909), subclose, up to 5 mm broad, lamella-edge slightly eroded to smooth, concolorous to side; lamellulae common, of 3 lengths. Stipe 42 × 3 mm, central cylindrical, equal, radicant; whitish to light brown (OAC 909/ 801) to dark ochraceous brown (OAC 796), unchanging when injured; surface squamulose towards the apex, then glabrous and striate bellow the ring; ring with median to slightly superior position, thin with double edge; context white (OAC 909), hollow.

Basidiospores 8.7–9.7(–10.7) × 5.6–6.6 µm, Q = 1.43–1.64, Qm = 1.47, ellipsoid in side view, thin to slightly thick-walled, hyaline, dextrinoid, cyanophilous, metachromatic; germ pore absent. Basidia (19.4–)21.9–24(–27.5) × 8.7–10.7 µm, clavate, hyaline, 4-spored; sterigmata up to 5 µm high. Pleurocystidia absent. Lamella edge sterile, with abundant heterogeneous cheilocystidia. Cheilocystidia 24–27.5 × 5.1–8.2 µm, slender clavate to sometimes broadly capitate, hyaline, thin-walled. Lamella trama regular to subregular, composed by hyphae (3.5–)4.6–5.6 µm in diam., colorless, thin-walled. Pileus covering a hymeniderm with ellipsoid, broadly clavate to sinuously slender clavate terminal elements, pale to brownish pigmented, measuring (11.2–)27.5–34.7(–51) × 6.6–9.7(–14.8) µm, thin-walled. Clamp connections absent from all examined tissues.

Distribution

Known only from the type locality.

Figures

Fig. 2. Chlorophyllum tenue E.Falcão, Ferretti-Cisn., Silva-Filho, Koroiva & Wartchow sp. nov. (holotype, JPB [66971]), general aspect. A. Pileus. B. Hymenophore. Scale bars = 20 mm.

Fig. 3. Chlorophyllum tenue E.Falcão, Ferretti-Cisn., Silva-Filho, Koroiva & Wartchow sp. nov. (holotype, JPB [66971]), line drawings of microstructures. A. Basidiospores. B. Basidia. C. Cheilocystidia. D. Pileus covering elements. Scale bars = 10 µm.

Fig. 4. Chlorophyllum tenue E.Falcão, Ferretti-Cisn., Silva-Filho, Koroiva & Wartchow sp. nov. (holotype, JPB [66971]), microstructures. A. Basidia. B. Basidiospores under Melzer’s reagent. C. Basidiospores in Cresyl Blue mounts. D. Lamella edge with two cheilocystidia. E–F. Pileus covering elements. Scale bars: A–F = 10 µm.