Triblidium rostriforme 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 rostriforme T. Lv & C. L. Hou sp. nov. Figs 4 , 5

Diagnosis.

Different from most Triblidium species by producing longer ascospores that have rostriform structures at the poles.

Holotype. On dead twigs of Rhododendron sp., CHINA, Yunnan Province, Lijiang, Laojunshan, 26.6831 N; 99.6997 E, alt. ca. 4056 m, 25 June 2011, C.-L. HOU 889 (BJTC 201906).

Description.

Ascomata erumpent from bark, elliptical in outline, 0.85-1.7 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 350-550 μm thick. Covering stroma 45-70 μm thick, consisting of an outer layer of highly melanized hyphae with some host tissues incorporated into the surface and an inner layer of hyaline hyphae. Basal layer 40-80 μm thick, composed of a lower, highly melanized layer with hyaline hyphae towards the internal matrix of the stroma which is 40-98 μm thick, composed of textura intricata. Subhymenium 25-45 μm thick, consisting of hyaline textura angularis. Excipulum moderately developed, formed by marginal paraphyses. Paraphyses 180-240 × ca. 1 μm, filiform, occasionally branched, sparsely guttulate, guttulae visible in water and IKI but disappearing in both lactophenol solution and 5% KOH. Asci ripening sequentially, 160-220 × 15-25 μm, cylindrical, thin-walled, without circumapical thickening, rounded at the apex, 8-spored. Ascospores 35-50 × 12-20 μm, L/W ratio of 2.0-3.8 (average ratio of 2.55), elliptical, with rostriform structures at the poles, hyaline, at first aseptate, becoming muriform at maturity, with usually 6 transverse septa and a few longitudinal and oblique septa, without gelatinous sheath, inamyloid in IKI.

Conidiomata and zone lines not seen.

Etymology.

From Latin, rostriforme , referring to the beak-like protrusions observed at the ascospore poles.

Additional specimen examined.

On dead twigs of Rhododendron sp., CHINA, Yunnan Province, Lijiang, Laojunshan, 26.6702 N; 99.7002 E, alt. ca. 4110 m, 24 June 2011, C.-L. HOU 851A (BJTC 201907).

Comments.

Triblidium rostriforme is similar to T. carestiae (De Not.) Rehm but T. carestiae commonly has asci with 3-8 ascospores, ascospores with usually 7-14 transverse septa and ramose, multi-guttulate paraphyses.

Figures

Figure 4. Triblidium rostriforme (Holotype, BJTC 201906) on Rhododendron sp. twig A, B mature dried ascomata observed under a dissecting microscope C dead ascospores in water D rostriform structure of ascospores.

Figure 5. Triblidium rostriforme (Holotype, BJTC 201906) A ascoma in median vertical section B paraphyses, mature asci with ascospores and immature ascus C dead ascospores in water.