Metacampanella subtricolor T. Bau & W. N. Hou, 2024

Hou, Wei-nan, Ganbaatar, Burenbaatar & Bau, Tolgor, 2024, Two new species of Metacampanella (Agaricales, Marasmiaceae) from China and Mongolia, MycoKeys 108, pp. 227-247 : 227-247

Metacampanella subtricolor T. Bau & W. N. Hou sp. nov.

Figs 2 C, D , 4

Type material.

Holotype. China • Inner Mongolia, Tongliao City, Daqinggou national nature reserve , 16 July 2023, 42 ° 49 ′ 20 ″ N, 122 ° 15 ′ 42 ″ E, alt. 313 m, Weinan Hou, H 2307120 ( FJAU 69309 )

Etymology.

“ subtricolor ” refers that this species is similar to Metacampanella tricolor .

Diagnosis.

Pileus is milky white, with furrowed edges and frosted surface. The stipe is finely scaly and black at base. Basidiospores are ellipsoid. Cheilocystidia tetrapyrgoid. Caulocystidia two types: a. tetrapyrgoid, b. individual arboreal dermatocystidia.

Description.

Pileus 3–6 mm, bell-shaped to hemispherical when young, and then gradually flattened, with a slight uplift in the center and wavy edges. The surface of the cap is densely covered with white powder frost, membranous, milky white to light yellow when young, light yellowish brown to brown in the center when mature, white to light yellow on the edge, with shallow grooves, membranous. Context milky white, thin. Lamellae cream to light yellowish brown, distant ( L = 10–12, I = 1–2), decurrent. Stipe 4–6 × 1–2 mm thick, cylindrical, equal thick or tapering downward. The top of the stipe milky white to light yellow brown, the middle is brown, slightly transparent, and the base dark brown to black and the surface white fine scales, fibrous, hollow.

Basidiospores 7.7–10 × 4.5–6 µm, Q = 1.7, ellipsoid, colorless, transparent, thin-walled, non-amyloid. Basidia 24–30 × 8–11 µm, clavate, 4 (2) - spored, colorless, transparent, thin-walled, base with clamp connections. Basidioles 20–23 × 5–8 µm, clavate or subfusiform, thin-walled. Trama hyphae of lamellae irregularity, 3–4.9 µm in width, with clamp connections and thick-walled. Cheilocystidia tetrapyrgoid, 18–27 × 5–8 µm, cylindrical, apex with or without a swollen obovate, base irregularly branched, surface protrusions, colorless, transparent, thick-walled. Pleurocystidia absent. Terminal cellular elements of pileipellis tetrapyrgoid, 20–36 × 4–7 µm, colorless, thick-walled. Pileipellis interwoven hyphae, 3.4–5.6 µm in width, pale yellow, transparent, verrucous surface, thick-walled. Caulocystidia two types: a. tetrapyrgoid, 11–22 × 4–7 µm, pale yellow, thick-walled, cylindrical, with spherical or ellipsoid cells at the top and protrusions on the surface; b. individual arboreal dermatocystidia. Stipitipellis composed of cylindrical hyphae, 2.9–4.7 µm, parallel, yellowish brown, thick-walled. Trama hyphae of stipe composed of cylindrical hyphae, 6.2–8 µm in width, parallel, colorless, transparent, thick-walled. Clamp connections present in all tissues.

Habitat and distribution.

Summer-growing, on the residues of Artemisia halodendron Turcz. ex Bess. Currently only known from northeast China.

Additional specimens examined.

China • Inner Mongolia, Tongliao City, Naiman Banner, Xinglongnuma Forest Farm , 12 July 2022; 43 ° 23 ′ 31 ″ N, 122 ° 12 ′ 20 ″ E, alt. 329 m, Tolgor Bau, Fang Guo, gf 2234 ( FJAU 67070 ) . China • Inner Mongolia, Tongliao City, horqin left back banner, Nugustai Town , 14 July 2022, 43 ° 23 ′ 48 ″ N, 122 ° 24 ′ 53 ″ E, alt. 311 m, Tolgor Bau, Weinan Hou, H 220752 ( FJAU 67068 ) . China • Inner Mongolia, Daqinggou national nature reserve , 16 July 2023, 42 ° 49 ′ 18 ″ N, 122 ° 15 ′ 31 ″ E, alt. 312 m, Tolgor Bau, Weinan Hou, H 2411102 ( FJAU 69310 ) .

Notes.

This species is similar to Metacampanella subtricolor with respect to morphological characteristics. Caulocystidia of Metacampanella subtricolor comprise two types: a. tetrapyrgoid, b. individual arboreal dermatocystidia, but caulocystidia of Metacampanella tricolor is composed of three types: a. long cylindrical or long clavate, b. U-shape, c. a few short clavate, base with irregular protrusion.

Figures

Figure 2. Basidiomata A, B Metacampanella coprophila C, D Metacampanella subtricolor E, F Metacampanella tricolor. Scale bars: 5 mm.

Figure 4. Metacampanella subtricolor A basidiomata B basidiospores C basidia D basidioles E cheilocystidia F pileipellis G stipitipellis. Scale bars: 1 mm (A); 5 µm (B); 15 µm (C – G).