Agrocybe eduardii Kiyashko & E. F. Malysheva

Lei, Chunyu, Deng, Guiyin, Huang, Jiahui, Shen, Yalun, Yan, Wenbo, Tian, Enjing & Fu, Yongping, 2025, New species and newly recorded species of the family Strophariaceae (Agaricomycetes, Agaricales) in China, MycoKeys 124, pp. 309-329 : 309-329

Agrocybe eduardii Kiyashko & E. F. Malysheva , Nova Hedwigia 115 (1–2): 185 (2022)

Figs 6 , 7

Description.

Pileus 60–66 mm in diam, initially hemispherical, becoming flattened at maturity, and the margin more or less recurved in age, pastel yellow (2 A 4) to cognac (6 E 7) the surface slightly viscid when moist, appearing patchily cracked. Context 5 mm thick, milk white (1 A 2), staining cream to pale yellow (2 A 3) when bruised, without distinctive odor, and of firm texture. Lamellae annexed, of unequal width, initially sunburn (6 D 5), becoming grayish orange (5 B 5) at maturity, 2–3 mm broad, L = 44–58, I = 1–4, crowded, edges even. Stipe 50–67 mm long, 6–8 mm wide, central, cylindrical to clavate, initially milk white (1 A 2) and fading to nearly white at maturity, but turning dark brown (7 F 8) when handled, thickened near the base, straight or slightly curved, and hollow inside.

Basidiospores 10–13.6 × 5.4–7.4 μm, Q = 1.6–1.8, Qm = 1.71 ± 0.11, in face view elliptical or oblong, in side view inequilateral, wall smooth and thick, with a distinct germ pore (1–1.4 μm wide) at the apex, golden yellow to brownish yellow (5 B 7–5 C 7) in KOH, containing either no oil droplets or multiple oil droplets internally. Basidia 25.1–34.7 × 7.8–8.9 µm, 2 - or 4 - spored, clavate, hyaline in KOH. Pleurocystidia 32.2–44.3 × 12.4–17.3 µm, ventriform, generally broadly utriformnon-mucronate, sometimes inflated, often pedicellate, with a short stalk at the base and obtusely rounded at the apex, thin-walled, hyaline in KOH. Cheilocystidia abundant, (28.4 –) 33.1–47.1 × 10.3–16.7 µm, flask-shaped to subclavate, thin-walled, smooth, with a hyaline or straw yellow (3 B 4) inclusion in KOH. Caulocystidia not observed. Gill trama of parallel hyphae, 3.7–19 μm in diam, thin-walled, hyaline in KOH. Pileipellis a hymeniderm composed of clavate, occasionally coralloid elements 18.2–33.9 × 5.8–12.5 μm, terminal cells thin-walled, hyaline in KOH. Clamp connections present in all tissues.

Habitat.

Solitary on trunk of broad-leaved trees or on the ground in coniferous and broad-leaved mixed forests in summer and fall.

Distribution.

Russia ( Kiyashko et al. 2022), China (new distribution).

Specimens examined.

China • Jilin, Changbai Mountain Nature Reserve, West Mountain , elev. 736 m, 42°24'23"N, 128°28'23"E, solitary on trunk of broad-leaved trees, 24 September 2024, Bai Wang, HMJAU 37438 ; • Jilin, Baishan City, Jiangyuan County, Sihai Forest Farm , elev. 830 m, 41°56'12.9"N, 126°25'6.6"E, solitary on the ground in coniferous and broad-leaved mixed forests, 11 September 2005, Tolgor Bau, HMJAU 5348 ; • Jilin, Antu County, Erdaobaihe Town, Huangsongpu Forest Farm , solitary on the ground in coniferous and broad-leaved mixed forests, 9 August 2009, Xin Jin, HMJAU 23902 ; • Jilin, Antu County, Erdaobaihe Town, Huangsongpu Forest Farm , solitary on the ground in coniferous and broad-leaved mixed forests, 9 August 2009, Tolgor Bau, HMJAU 24841 .

Comments.

Agrocybe eduardii from Russia was recently described as a new Agrocybe species ( Kiyashko et al. 2022). It is characterized by a vividly colored yellow-orange to red-orange pileus, well-developed partial veil persisting as felty patches around the pileus margin, roughly-fibrous to subsquarrose-squamulose stipe with a bulbous base; rather large basidiospores (10–13.6 × 5.4–7.4 μm) with a truncate apex formed by a large germ pore; variable cheilocystidia in shape; and hymeniform pileipellis.

The specimens collected in China in this study were morphologically similar to the original description of A. eduardii . In the phylogenetic analyses (Fig. 1 ), the Chinese samples were grouped with the type of A. eduardii monophyletically with high statistical support.

In the phylogram, A. eduardii was sister to A. dura with high statistical support (Fig. 1 ). However, morphologically, the former has a vivid orange pileus, margin becoming strongly revolute and lacerate in age, and flask-shaped to subclavate cheilocystidia with a hyaline or straw yellow inclusion in KOH; the latter has a cream-white to pale yellow pileus, short-stipitate vesiculose to broadly ellipsoid or medially constricted elongate-clavate cheilocystidia, and vesiculose to broadly ellipsoid or clavate pleurocystidia with upper-medial constriction ( Jin 2012).

Figures

Figure 1. Bayesian inference (BI) phylogram of Agrocybe, Pholiota and Pyrrhulomyces based on dataset (ITS + nrLSU). PPs> 0.95 and bootstrap values > 70 % are shown. Types are indicated in green, and the new species and the species newly recorded in China in this study are in red.

Figure 6. Basidiomata of Agrocybe eduardii A, B. (HMJAU 37438). Photos by Bai Wang. Scale bars: 1 cm.

Figure 7. Microcharacters of Agrocybe eduardii (HMJAU 37438). Drawings by Chunyu Lei. A. Basidiospores; B. Basidia; C. Pleurocystidia; D. Cheilocystidia; E. Pileipellis. Scale bars: 10 µm (A); 20 µm (B – E).