Entoloma gatesianum Karstedt & Capelari

Karstedt, Fernanda, Bergemann, Sarah E., Gates, Genevieve, Ratkowsky, David, Cunha, Kelmer Martins & Capelari, Marina, 2024, Species of Entoloma (Entolomataceae) with cuboidal basidiospores from Brazil, Phytotaxa 654 (1), pp. 1-76 : 40-42

Entoloma gatesianum Karstedt & Capelari , sp. nov.

Figs. 16 , 17k–m , 34d

MB 838592

Etymology:— Gatesianum in honor of Dr Genevieve Maria Gates for her contribution to the knowledge of Entolomataceae and who likes the color lilac.

Diagnosis:— Entoloma gatesianum is characterized by the combination of a lilac to slightly brownish lilac basidiome, cuboidal basidiospores, scattered pseudocystidia and variable but often fusoid cheilocystidia with a constricted apex.

Type:— BRAZIL. Espírito Santo: Santa Teresa, Augusto Ruschi Biological Reserve , 4 December 2012, A.E. Magnago ACM498 (Holotype, FLOR) .

Description:— Pileus 20–70 mm diam., conical, not translucent-striate or only at margin, lilac or slightly brownish pink, rarely hygrophanous, slightly adpressed-fibrillose, margin involute. Pileus context not observed. Lamellae adnexed or almost free, ventricose, pinkish yellow to slightly ochre near the pileus margin, crowded with three tiers of lamellulae; margins concolorous with faces, entire or slightly irregular. Stipe 75–150 × 4–13 mm, slightly attenuated upwards, circular, centrally attached, whitish lilac towards the base, becoming greenish where bruised, glabrous, longitudinally adpressed-fibrillose, twisted, fibrous, hollow, with white basal tomentum. Odor and taste indistinct. Spore print brownish pink.

Basidiospores cuboidal with an obvious hilar appendix, excluding the projections, 7.5–10 × 8.7–11 µm [xm = 8.97 (± 0.54) × 9.31 (± 0.66) µm, Q = 1–1.16, Qm = 1.03 (± 0.07), n = 21] diagonally 10–12.5 × 11.2–12.5 µm [xm = 11.02 (± 0.56) × 11.46 (± 0.46) µm, Q = 1–1.25, Qm = 1.04 (± 0.06), n = 40/2], thin-walled. Basidia clavate, (37–)47–62 × 12.5–16 µm (n = 40/2), hyaline or with brownish intracellular pigment, thin-walled, 4-sterigmate, rarely 2-sterigmate. Cheilocystidia cylindrical, cylindrical-tortuose, sinuous, hyphoid, fusoid-ventricose, ampuliform, fusoid-ampuliform, often with constricted apex, 37–118 × 5–14 µm (n = 40/2), with straw yellow, brownish or hyaline intracellular pigment, thin-walled or slightly thickened. Pleurocystidia absent. Pseudocystidia scattered to rare, hyphoid, cylindrical or fusiform, sometimes branched, not exceeding the height of the hymenium, 2.5–5 µm diam. (n = 24/2), hyaline or straw yellow, refractive in ammonia solution, thin-walled. Lamellar trama of parallel, cylindrical, broadly cylindrical or narrowly fusiform hyphae, 2.5–21 µm diam. (n = 42/2), hyaline or with straw yellow or brownish intracellular pigment, thin-walled; sub-hymenium branched, hyaline. Pileitrama composed of radially-arranged, cylindrical or inflated hyphae, 2.5–22 µm diam. (n = 40/2), hyaline or with brown intracellular pigment, thin-walled. Pileipellis a cutis of prostrate, parallel or loosely entangled, cylindrical hyphae, 2.5–12.5 µm diam. (n = 40/2), hyaline, or with straw yellow or brownish intracellular pigment, thin-walled; terminal hyphae cylindrical with rounded apex. Stipitipellis a cutis, hyphae prostrate, 3.7–10 µm diam. (n = 40/2), cylindrical, with straw yellow or brown-yellow intracellular pigment, thin-walled or slightly thickened. Caulocystidia absent. Clamp connections present in all tissues. Refractive hyphae and hyphae with brilliant granules present in the trama of the lamella and pileus.

Habitat:—Solitary, in soil, in the Atlantic Forest biome.

Distribution:—To date collected only in Espírito Santo, Brazil, the type locality.

Additional material examined:— BRAZIL. Espírito Santo: Santa Teresa, Augusto Ruschi Biological Reserve , 4 December 2012, A.E. Magnago ACM499 ( FLOR) .

Comments:— Entoloma gatesianum is closely related to the orange-colored Entoloma cf. lactifluum sp.nov. (TJB7962 and TJB8753) and E. manausense sp.nov. Entoloma cf. lactifluum differs in the orange basidiome colors, and an exudate that varies in color from clear, pink to orange, in addition to an absence of cheilocystida (Heim 1936, Romagnesi 1941). Entoloma manausense differs in its blue basidiome, abundant pseudocystidia and clavate and nonfusoid cheilocystidia with strangulated apex.

Figures

FIGURE 16. Entolomagatesianum:a–b.basidiospores:a. ACM499; b. ACM498;c–d. basidia:c.ACM499;d.ACM498;e–f.cheilocystidia: e. ACM499; f. ACM498; g. pseudocystidia (ACM498), h. pileipellis (ACM499). Scales: a–g: 10 µm, h: 20 µm.

FIGURE 17. Microphotography of basidiospores in electron microscopy: a–c. E. dragoluteum (FK2120); d–f. Entoloma dragorufescens (FK2102); g–j. E. fraternum (B3074); k–m. E. gatesianum (ACM499). Scale: 5 µm.

FIGURE 34. Basidiomas: a–b. Entoloma amazonicum: a. FK1815; b. FK1814; c. E. luteobrunneum (FK1693); d. E. gatesianum (ACM498). Photos: a–c: F. Karstedt; d: A.C. Magnago. Scale: 1 cm.