Triblidium longisporum C. J. Y. Li, K. W. T. Chethana & Q. Zhao, 2025

Triblidium longisporum C. J. Y. Li, K. W. T. Chethana & Q. Zhao sp. nov.

Fig. 3 View Figure 3

Etymology.

The specific epithet refers to the long ascospores, ‘ longi ’ (lat.) = long, ‘ sporum ’ (lat.) = spore.

Holotype.

HKAS 145642 View Materials .

Diagnosis.

It is similar to T. stipitatum , but T. longisporum has soft orange hymenium without stipes, simple basal stroma structures and slightly shorter asci and ascospores.

Description.

Saprobic on the bark of the living Fagaceae tree. Sexual morph: Apothecia 1.3–2.3 (– 3, 1) mm wide ( x ̄ = 1.8 μm, n = 20) when fresh, 1.1–1.9 (– 2.7) mm wide ( x ̄ = 1.6 μm, n = 20), 0.5–0.8 μm high ( x ̄ = 0.6 μm, n = 10) when dried, scattered, superficial, discoid, sessile, erumpent from the bark, initially growing as a cleistohymenial development, the hymenium tightly protected by excipulum when immature, splitting to expose hymenium by usually 6–8 teeth-like lobes in the surface in a humid environment, black (# 4 a 4750) surface with polygonal areolae, becoming warty bulges after opening. Discs flat, circular to irregular shape, very soft orange (# dac 696) when fresh, sub-circular to irregular shape, the edges irregularly curl towards the centre, translucent dark orange (# 6 d 531 f) when dried. Receptacles rough and black when fresh, sculptured with polygonal areolae or wrinkled on the surface when dried. Lips absent. Covering stroma 80–115 (– 135) μm thick, comprised of carbonised, textura angularis cells and the inner layers of hyaline, textura angularis to globulosa cells. Hymenium 330–400 μm ( x ̄ = 360 μm, n = 10) thick, hyaline to pale yellow. Subhymenium 45–85 μm ( x ̄ = 64 μm, n = 15) thick, comprised of hyaline, textura angularis cells, 4.0–9.2 μm ( x ̄ = 6.1 μm, n = 40) in diam. Internal matrix of stroma (110 –) 140–270 μm ( x ̄ = 195 μm, n = 30) thick, well-developed, comprised of hyaline, textura intricata hyphae, 1.6–3.3 μm ( x ̄ = 2.2 μm, n = 40) in diam., non-gelatinous. Basal stroma (40 –) 56–128 (– 154) μm ( x ̄ = 89 μm, n = 40) thick, well-developed, the outer layers comprised of carbonised, gelatinous, black red textura angularis cells, 3.1–6.0 (– 7.4) μm ( x ̄ = 4.7 μm, n = 40) in diam., the inner layers comprised of hyaline cells, (3.8 –) 5.1–11.3 (– 15.7) μm ( x ̄ = 7.2 μm, n = 70) in diam., partial elements orientated at a high angle to receptacle surface, non-gelatinous. Paraphyses 340–390 × 1.8–2.9 μm ( x ̄ = 360 × 2.3 μm, n = 40) wide, hyaline with some tiny yellow oil drops, filiform, occasionally branched at the tips, aseptate, apically irregular-shaped and surrounded by a thin, gelatinous sheath. Asci ripening sequentially, 250–336 × 22–30 μm ( x ̄ = 280 × 26 μm, n = 30), unitunicate, 8 - spored, clavate, apically rounded without amyloid reaction in Melzer’s reagent, tapering to a fragile pleurorhynchous subtruncate base, croziers absent. Ascospores 160–196 × 5.9–10.5 μm ( x ̄ = 176 × 7.9 μm, n = 40, Q = (16.1) 18.8–30.3, Qm = 22.7 ± 3.4), overlapping fascicles, long acicular, transverse-septate, hyaline, 28–31 - septate when mature, with a single oil drop in each cell, sharp ends, wide at the top and tapering downwards, thin and rough-walled with fine verrucae. Asexual morph: Undetermined.

Material examined.

China • Yunnan Province, Dali City, Jinguangsi Protection Zone , altitude 2,380 m, on the living bark of Fagaceae tree, 27 July 2024, Cuijinyi Li LCJY-1700 ( HKAS 145642 View Materials , holotype) ; • ibid., Cuijinyi Li LCJY-1691 ( HKAS 145640 View Materials , paratype) .

Notes.

Our collection was placed sister to T. stipitatum , with the Maximum Likelihood bootstrap support of 86.5 % in the SH-aLRT test, 92 % in the UFB method and a Bayesian posterior probability of 1.0 (Fig. 1 View Figure 1 ). Triblidium longisporum can be distinguished from other known species by its exceptionally long ascospores, with the exception of T. stipitatum . This species differs from T. stipitatum by its soft orange hymenium, lack of stipes, simple structures at the covering and basal stroma, smaller asci (250–336 μm vs. 272–355 μm) and shorter ascospores (160–196 μm vs. 187–226 μm). Based on the molecular analyses, the ITS sequence of T. longisporum exhibited a 11.4 % difference with 34 gaps (60 / 523) to T. stipitatum (isolate: HKAS 145641 ), while the LSU sequence showed a 5.7 % difference with one gap (48 / 838) to T. stipitatum (isolate: HKAS 145641 ) and the mtSSU sequence displayed a 3.7 % difference with 10 gaps (31 / 831) to T. stipitatum (isolate: HKAS 145641 ).