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

Fig. 4

Etymology.

The specific epithet refers to the presence of stipes, ‘ stipitatum ’ (lat.) = stipitate.

Holotype.

HKAS 145641.

Diagnosis.

It is similar to T. longisporum, but differs by having a stipitate, greyish-white disc, a basal stroma, consisting of three parts and slightly longer asci and ascospores.

Description.

Saprobic on the bark of the living Fagaceae tree. Sexual morph: Apothecia 1.9–3.2 mm wide (x ̄ = 2.6 μm, n = 30) when fresh, 1.6–2.6 (– 3.1) mm wide (x ̄ = 2.1 μm, n = 20), (0.5 –) 0.7–1.0 μm high (x ̄ = 1.6 μm, n = 20) when dried, scattered, superficial, cupulate, stipitate, erumpent from the bark, initially growing as a cleistohymenial development, obconical without a point, the hymenium tightly protected by excipulum when immature, splitting to expose hymenium by eight 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 to slightly detained in the centre, circular to irregular-shaped, greyish-white (# abb 3 b 6) when fresh, triangular to angular-shaped, the edges curling towards the centre, desaturated dark green (# 9 eb 07 c) when dried. Receptacles rough and black when fresh, sculptured with polygonal areolae when dried. Stipes 0.5–1.0 mm wide, 0.6–1.0 mm high when dried, concolorous to the receptacles. Lips absent. Covering stroma 63–138 μm thick, comprised of carbonised, textura angularis cells and the inner layers hyaline, textura angularis to globulosa cells. Hymenium 378–432 μm (x ̄ = 399 μm, n = 20) thick, hyaline. Subhymenium 52–111 μm (x ̄ = 85 μm, n = 40) thick, comprised of hyaline, textura globulosa to angularis cells, 4.5–9.5 (– 11.3) μm (x ̄ = 7.1 μm, n = 80) in diam. Internal matrix of stroma 135–220 μm (x ̄ = 180 μm, n = 40) thick, well-developed, non-gelatinous, divided into three parts, part I near subhymenium comprised of dense and pale brown, textura intricata hyphae, 1.5–2.5 μm (x ̄ = 2.0 μm, n = 40) in diam.; part II in the middle, 37–74 μm wide, comprised of carbonised, black red (# 28171 a), textura angularis cells same as the ectal excipulum; part III (stipe) comprised of hyaline and densely parallel hyphae, mixed with large refraction resin materials, hyphae 1.7–2.5 μm (x ̄ = 2.1 μm, n = 60) in diam. Basal stroma 65–140 μm (x ̄ = 101 μm, n = 60) thick, well-developed, the outer layers comprised of carbonised, black red, textura angularis cells, 2.9–5.8 μm (x ̄ = 4.3 μm, n = 100) in diam., the inner layers comprised of hyaline cells, 5.5–10.3 (– 12.7) μm (x ̄ = 8.0 μm, n = 80) in diam., partial elements orientated at a high angle or vertical to receptacle surface, slightly gelatinous. Paraphyses 315–345 × 1.7–2.7 μm (x ̄ = 332 × 2.1 μm, n = 40) wide, hyaline, filiform, unbranched, aseptate, apically rounded, slightly swollen and waved, surrounded by a thin, gelatinous sheath. Asci ripening sequentially, 272–355 (– 373) × 21–30 μm (x ̄ = 312 × 25 μm, n = 40), unitunicate, 8 - spored, clavate, apically ellipse, without amyloid reaction in Melzer’s reagent, tapering to a fragile pleurorhynchous, subtruncated base, croziers absent. Ascospores 187–226 (– 241) × 6.8–10.5 μm (x ̄ = 206 × 7.9 μm, n = 40, Q = (17.8) 22.9–31.3, Qm = 26.3 ± 3.1), overlapping fascicles, long acicular, transverse-septate, hyaline, 24–33 (– 38) - 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-1695 (holotype HKAS 145641); • ibid., 24 July 2024, Cuijinyi Li LCJY-1642 (paratype HKAS 145639).

Notes.

Triblidium stipitatum is distinguished from all other known species by its well-developed stipe and the special excipulum structure. It is closely related to T. longisporum, based on both morphological and phylogenetic analysis, but can still be easily distinguished. Triblidium stipitatum can be differentiated from the latter species by the presence of stipes, greyish-white hymenium, a basal stroma consisting of three parts (from top to bottom: pale brown intricate hyphae, black red angularis cells and hyaline parallel hyphae mixed with large refraction resin materials), as well as slightly longer asci (272–355 μm vs. 250–336 μm) and ascospores (187–226 μm vs. 160–196 μm). The molecular analyses were shown in the note of T. longisporum.