Pluteus aurantioruber Jiang Xu & T.H. Li, 2023

Xu, Jiang, Hosen, Md. Iqbal, Zhang, Ming & Li, Tai-Hui, 2023, Pluteus aurantioruber, a new species of Pluteus section Celluloderma (Pluteaceae) from China, Phytotaxa 629 (1), pp. 65-74 : 68-69

Pluteus aurantioruber Jiang Xu & T.H. Li , sp. nov., Figs. 2 , 3

Fungal Name: FN 571224; MycoBank: MB 849035.

Etymology:—from Latin aurantiacus = orange, and ruber = red, referring to the orange-red pileus.

Diagnosis:—Morphologically similar to Pluteus aurantiorugosus but differing mainly by the cheilocystidia with a short to long apical rostrum, clustered caulocystidia, larger basidiospores (6.0‒8.0 × 5.5‒7.0 μm), and distinct nrITS sequence.

Description:— Basidiomata small. Pileus 8‒20 mm in diam., obtusely conical to hemispherical when young, expanding to convex, plano-convex or applanate, often with a low umbo, non hygrophanous, striate at margin, bright orange-red (7A7‒7A8) to vivid reddish orange (8A7‒8A8) when young, orange (6A7‒6A8) to orange-yellow (4A8‒5A8) when mature, glabrous; margin indistinctly striate, or lobed and becoming finely rimose, sometimes eroded. Lamellae free, moderately crowded, with lamellulae, ventricose, up to 3 mm broad, whitish to yellowish (5A4), sometimes eroded near the pileus margin. Stipe 10‒34 × 1‒2.5 mm, cylindrical, equal or slightly enlarged towards base, slightly hollow to solid when mature, yellowish (4A7‒4A8) to concolorous with the pileus when mature, pale orange (7A4‒7A5) at the base, somewhat translucent, distinctly squamulose over whole length. Context whitish in pileus and yellowish in stipe. Smell indistinct. Taste not recorded. Spore print pale pinkish.

Basidiospores [60/3/2] (5.5‒)6.0‒8.0(‒8.5) × (5.0‒)5.5‒7.0 μm (L av = 7.0, W av = 6.1, Q = 1.07‒1.23; Q m = 1.14), subglobose to broadly ellipsoid, slightly thick-walled. Basidia 18‒25 × 8‒11 μm, clavate, 4-spored, hyaline or with refringent content, thin-walled. Pleurocystidia 25‒50 × 10‒22 μm, rare, scattered, clavate to broadly clavate, non-rostrate, hyaline, thin-walled. Lamellar margin sterile. Cheilocystidia 30‒65 × 10‒25 μm, abundant, clavate to broadly clavate, with a short to long rostrate apex (up to 20 μm), hyaline, thin-walled. Pileipellis an epithelium, made up of subfusiform to clavate elements, 25–62 × 12–30 μm, filled with intracellular pigment yellowish brown in 5% KOH, thin-walled. Stipitipellis a cutis of cylindrical thin-walled hyphae 4‒15 μm diam, colorless or with brownish intracellular pigment in 5% KOH. Caulocystidia 26‒50 × 10‒21 μm, clavate to fusiform, non-rostrate, thin-walled, present over the entire length of the stipe, usually in clusters, colorless or with brownish intracellular pigment in 5% KOH. Clamp connections absent in all parts examined.

Ecology and distribution:—Known from South China, scattered on the ground in roadside green belt ( Buxus spp ., Ligustrum spp .) or on swampy ground among mosses ( Bryoandersonia spp .) near Ficus spp .

Holotype:— CHINA. Guangdong Province, Guangzhou City, Baiyun District, Baiyun Experimental Base of Guangdong Academy of Agricultural Sciences , 23° 23′ 49″ N, 113° 26′ 20″ E, elev. 30 m, on the ground with moss ( Bryoandersonia sp. ), 7 May 2021, Jiang Xu XJ 1478, GDGM89520 (holotype!; GenBank OP522368 –ITS).

Additional collection examined:— CHINA. Guangdong Province: Guangzhou City, Guangdong Academy of Agricultural Sciences, 23°8′54″ N, 113°21′00″ E, elev. 20 m, in roadside green belt, 6 September 2016, Jiang Xu XJ1342, GDGM89521 (GenBank OP522369‒ITS).

Figures

FIGURE 2. A, B Mature basidiomata of Pluteus aurantioruber (A. GDGM89520, holotype, B. GDGM89521). Scale bar: A‒B = 1 cm. Photos by: Jiang Xu

FIGURE 3. A. Basidiospores. B. Basidia. C. Cheilocystidia. D. Pleurocystidia. E. Pileipellis elements. F. Caulocystidia.; Scale bar: A‒F = 10 μm. Drawings by: Jiang Xu