Triblidium yunnanense T. Lv & C. L. Hou

Lv, Tu, Hou, Cheng-Lin & Johnston, Peter R., 2019, Three new species and a new combination of Triblidium, MycoKeys 60, pp. 1-15 : 1

Triblidium yunnanense T. Lv & C. L. Hou sp. nov. Figs 6 , 7

Diagnosis.

Different from T. hafellneri by its ascospores with 6-8 transverse septa, narrow asci and geographical range. Different from its phylogenetically closest relatives ( T. hubeiense and T. rostriforme ) by the size and the shape of ascomata and ascospores.

Holotype. On twigs of Rhododendron sp., CHINA, Yunnan Province, Lijiang, Laojunshan, 26.6571 N; 99.6944 E, alt. ca. 4070 m, 25 June 2011, C.-L. HOU 875A (BJTC 201903).

Description.

Ascomata erumpent from bark, circular or slightly irregular in outline, 0.5-0.8 mm diam., solitary, with a black (#211414) outer surface that is sculptured with polygonal areolae, opening by irregular splits to expose the hymenium. In median vertical section, ascomata 300-400 μm thick. Covering stroma 45-75 μm, consisting of an outer layer of highly melanized hyphae with remnants of host tissue incorporated into the outer surface and an inner layer of hyaline hyphae. Basal layer 45-88 μm thick, composed of an outer layer of highly melanized hyphae and short, thick, hyaline hyphae towards the internal matrix of stroma that is 60-85 μm thick, composed of thick hyphae. Subhymenium 35-59 μm thick, consisting of hyaline textura angularis. Excipulum 25-35 μm thick, formed by marginal paraphyses. Paraphyses 180-230 × 1-1.2 μm, filiform, often branched, multi-guttulate, guttulae visible in water and IKI but disappearing in both lactophenol solution and 5% KOH. Asci ripening sequentially, 150-200 × 13-18 μm, cylindrical, thin-walled, without circumapical thickening, rounded at the apex, 6-8-spored. Ascospores 20-30 × 10-15 μm, L/W ratio of 1.7-2.5 (average ratio of 1.99), ellipsoid, hyaline, at first aseptate, becoming muriform at maturity, with usually 6-8 transverse septa and a few longitudinal and oblique septa, without gelatinous sheath, inamyloid in IKI.

Conidiomata and zone lines not seen.

Etymology.

Referring to the Yunnan Province where the holotype specimens were collected.

Additional specimens examined.

On twigs of Rhododendron sp., CHINA, Yunnan Province, Lijiang, Laojunshan, 26.6741 N; 99.6930 E, alt. ca. 4040 m, 11 July 2007, C.-L. HOU 470A (BJTC 201904). On dead twigs of Rhododendron sp., CHINA, Sichuan Province, Mt. Emeishan, 29.5185 N; 103.3329 E, alt. ca. 3010 m, 12 July 2014, C.-L. HOU 1179 (BJTC 201905).

Comments.

Triblidium yunnanense is similar to T. hafellneri Magnes, but the latter has asci 20-25 μm wide, ascospores with 7 transverse septa and occurs on Vaccinum ovatum , Calluna vuglaris , Salix spp., and Nothofagus antarctica in Europe and the Americas. Triblidium yunnanense has a close relationship to the two other new species in this study, but T. rostriforme has larger ascomata, ascospores with special beak-like structures and T. hubeiense has larger ascomata, unbranched paraphyses, a moderately developed excipulum, a thicker covering stroma, basal layer and subhymenium.

Figures

Figure 6. Triblidium yunnanense (Holotype, BJTC 201903) on Rhododendron sp. twig A, B mature dried ascomata observed under a dissecting microscope C dead ascospores in water.

Figure 7. Triblidium yunnanense (Holotype, BJTC 201903) A ascoma in median vertical section B paraphyses, mature asci with ascospores and immature ascus C dead ascospores in water.