Tatraea aseptata H.L. Su & Q. Zhao, sp. nov. Fig. 1

MycoBank number: MB; Index Fungorum number: IF; Facesoffungi number: FoF 12892;

Etymology: Refers to aseptate ascospores

Diagnosis: Our new species is characterized by the mature and aseptate ascospores.

Saprobic on dead stems. Sexual morph: Apothecia 0.3 – 0.6 cm diam when fresh, up to 0.3 cm high when fresh, superficial, scattered, slightly leathery, shortly stipitate, Hymenium 150 – 230 µm thick, flat to slightly invaginate, surface smooth, grey to slightly reddish brown when fresh, brown when dry. Margin flat to slightly involute, light brown. Receptacle discoid to campanulate, light puce when fresh, brown when dry, rough. Hairs 40–85 × 6–8 µm (x̄ = 64 × 7 µm, n = 20), slightly needle-like with rounded apex, smooth, thick-walled, septate, hyaline, light brown. Ectal excipulum 90 – 290 µm thick, comprised of textura angularis cells, 5.0 – 20.0 × 4.0 – 13.5 µm (x̄ = 12.0 × 7.5 µm, n = 24), thin-walled, light yellow to light brownish. Medullary excipulum 485 – 725 µm thick, comprised of textura intricate cells, 3.5 – 7.0µm (x̄ = 4.4 µm, n = 25) diam, thin-walled, slightly lighter than ectal excipulum. Paraphyses 1.5 – 3.5µm (x̄ = 2.3 µm, n = 25) diam, equal to asci, filiform with obtuse apex, septated, unbranched, thin-walled, septate, hyaline. Asci 150 – 185 (– 190) × (12 –) 13 – 18 µm (`x = 171 × 15 µm, n = 24), clavate, rounded apex, wall apically thickened and laterally thin, with a ocular chamber, amyloid at apex, uniseriate, 8-spored, hyaline. Ascospores (120/4/2) (18.5 –) 21.0 – 28.0 (– 32.0) × 7.0 – 9.2 (– 10.0) µm, `(x = 24.2 × 8.2 µm, n = 119 , Q = 2.11 – 4.38, Q = 2.97 ± 0.35), reniform with sharp apexes, one oil guttule or multiguttules, most one oil guttule, aseptate, slightly smooth, slightly thick-walled, hyaline. Asexual morph: Unknown.

Material examined: China, Yunnan, Ailao Mountains, alt. 2428 m, on bark of a dead branch, 2 September 2021, H.L. Su, SHL206 (HKAS 124623, holotype), ibid., alt. 2328 m, on bark of a dead branch, 28 August 2021, H.L. Su, SHL51 (HKAS 124624, paratype).

Notes: Based on the phylogenetic tree obtained from ITS sequence analysis, our specimen is sister to Tatraea dumbirensis with considerable bootstrap support (88% MLBS/ 0.67BPPS). Tatraea has two accepted species, T. macrospora and T. dumbirensis. Compared our new species with T. macrospora and T. dumbirensis, the three species have different mature ascospores. Tatraea macrospora has 3–8-septate ascospores, T. dumbirensis has 1–2-septate ascospores, however, our new species has aseptate ascospores. Besides, Our species has light puce receptacle, however, T. macrospora and T. dumbirensis have shallow cream-colored to grayish receptacle.

Fig.1 Tatraea dumbirensis (HKAS***, holotype) a Habit. b–e Tatraea dumbirensis on substrate. f Vertical section of apothecia. g Excipulum. h Ectal excipulum. i Hair. j Paraphyses. k‒m Asci. n Asci in Melzer. o Apex of asci in Melzer. p Base of asci. q‒s Ascospores. t Ascospores in Melzer. Scale bars: f = 500μm, g = 100 μm, h‒n = 50 μm, o−t = 10 μm.