Triblidium hubeiense 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 hubeiense T. Lv & C. L. Hou sp. nov. Figs 2 , 3

Diagnosis.

Similar to Triblidium sherwoodiae but different by apically not swollen and unbranched paraphyses and homolateral curved ascospores, with a smaller L/W ratio of 1.4-2.3 (average ratio of 1.83) (average ratio of 2.52 for T. sherwoodiae ).

Holotype. On dead twigs of Rhododendron sp., CHINA, Hubei Province, Shennongjia National Nature Reserve, 31.4360 N; 110.3014 E, alt. ca. 2900 m, 23 July 2018, C.-L. HOU1350A (BJTC 201908).

Description.

Ascomata erumpent from the bark, circular or rectangular in outline, 1.3-2.0 mm diam., solitary or occasionally confluent, with a black (#211414) outer surface that is sculptured with polygonal areolae, opening by irregular splits to expose a yellow (#ffc14f) hymenium. In median vertical section, ascomata 500-600 μm thick. Covering stroma 270-300 μm thick near the central part of ascomata, decreasing to 65-110 μm at the edge, consisting of an outer layer of highly melanized hyphae with a few remnants of host tissue embedded in the surface and an inner layer of hyaline hyphae. Basal layer 65-160 μm thick, composed of highly melanized hyphae with hyaline hyphae towards the internal matrix of stroma that is 75-125 μm thick, composed of textura intricata. Subhymenium 45-75 μm thick consisting of small, irregular textura angularis. Excipulum absent. Paraphyses 200-230 × ca. 1 μm, filiform, multi-guttulate, guttulae visible in water and IKI but disappearing in both lactophenol solution and 5% KOH, not swollen and branched at the apex, extending past mature asci. Asci ripening sequentially, 160-200 × 15-24 μm, cylindrical, thin-walled, without circumapical thickening, rounded at the apex, 6-8-spored. Ascospores 20-30 × 12-18 μm, L/W ratio of 1.4-2.3 (average ratio of 1.83), ellipsoidal, often curved homolateral, hyaline, at first aseptate, becoming muriform at maturity, with 6-8 transverse septa and a few longitudinal and oblique septa, without a gelatinous sheath, inamyloid in IKI.

Conidiomata and zone lines not seen.

Known distribution.

Known from a single collection from Shennongjia National Nature Reserve, Hubei Province, China.

Etymology.

Referring to the Hubei Province where the specimen was collected.

Comments.

Triblidium hubeiense is similar to T. sherwoodiae Magnes and T. carestiae (De Not.) Rehm, but T. sherwoodiae has paraphyses with swollen terminal cell, straight ascospores and is only found on Pinus ponderosa ; T. carestiae commonly has 3-8 ascospores per ascus, ascospores usually with beak-like structure at poles, 7-14 transverse septa and apically branched paraphyses.

Figures

Figure 2. Triblidium hubeiense (Holotype, BJTC 201908) on Rhododendron sp. twig A, B mature dried ascomata observed under dissecting microscope C dead ascospores in water.

Figure 3. Triblidium hubeiense (Holotype, BJTC 201908) A ascoma in median vertical section B paraphyses, mature asci with ascospores and immature ascus C dead ascospores in water.