Violella yunnanensis C. J. Zhong & L. Hu sp. nov.

Fig. 3

Diagnosis.

The species is characterized by having esorediate, areolate to weakly warted thallus, hymenium heavily pigmented with Fucatus-violet pigment, brownish inner ascospore walls, and its chemistry (atranorin and fumarprotocetraric acid).

Type.

China. Yunnan Prov.: • Deqin Co., on the way from Yubeng Upper Village to Glacier Lake beside the observation platform in Meili Snow Mountain National Park, 28°23'56.37"N, 98°46'8.97"E, 3506 m, on bark, 22 April 2023, L. Hu et al. SDNU 20235026 (holotype).

Description.

Thallus crustose, areolate, weakly warted, consisting of discrete flattened to convex areoles (0.18 –) 0.23–0.28 mm diam., color grey to pale ocher, with crystals in the medulla. Soredia and isidia absent. Hypothallus not observed. Photobiont chlorococcoid, cells rounded to irregularly angular, (7 –) 8–10 (– 12) μm diam.

Apothecia rounded to irregular, single or clustered in groups of 2–3 and becoming confluent, (0.4 –) 0.8–1.75 (– 2) mm diam., base broadly adnate; disc ± flat to weakly convex, jet black and shiny; margin indistinct; “ thalline cushion ” present, visible from above and forming a thin white line at least when young, in section prosoplectenchymatous, variable in thickness, 25–100 (– 137.5) μm thick, clearly differentiated from subhymenium above and medulla below. Proper exciple similar in structure to the hymenium, hyphae radiate, similar to paraphyses, filled with Fucatus-violet pigment and often suffused with Cinereorufa-green. Epihymenium not differentiated. Hymenium 125–137.5 μm tall, densely inspersed with minute oil droplets; the Fucatus-violet pigment is concentrated at the base and the top of the hymenium and largely diffuse. Subhymenium consisting of a thin layer of ascogenous hyphae, 30–32.5 μm tall, filled like the hymenium with Fucatus-violet pigment but sometimes also infused with Cinereorufa-green pigment; differentiated hypothecium absent. Paraphyses branched, anastomosing, 2–2.5 μm wide; paraphyses’ tips not or scarcely expanded, 2.5–3 μm wide. Asci clavate, inner and outer walls staining blue, tholus strongly I + blue, pierced by a broad, conical non-amyloid structure, thus similar to the Biatora - type. Ascospores ellipsoidal, 2 per ascus (occasionally 1), beginning colourless and apparently with a single wall, eventually developing a secondary inner wall, which quickly turns brown while still in the ascus; outer wall thick, to 3 μm in some cases, the inner brown wall thin, often collapsing, live, healthy ascospores also with brown endospore, (43 –) 50.4 ± 5.37 (– 63) × (23 –) 28.15 ± 3.5 (– 38) μm in water, length / width ratio (1.53 –) 1.8 ± 0.14 (– 2); n = 20. Pycnidia not seen in Chinese materials.

Chemistry.

Spot test: thallus K + yellow, C –, P + orange-red, UV –; TLC: atranorin and fumarprotocetraric acid.

Ecology and distribution.

Found on twigs of Rhododendron and bark in subalpine and alpine regions. Collections came from elevations of 3500–3800 m in the northwest of Yunnan Province in China.

Etymology.

The specific epithet ‘ yunnanensis’ refers to the Yunnan Province, where this species was found.

Notes.

Violella yunnanensis is characterized by having esorediate, areolate to weakly warted thallus, hymenium heavily pigmented with Fucatus-violet pigment, brownish inner ascospore walls, and producing atranorin and fumarprotocetraric acid. Violella wangii has a similar habitat to this new species. Specimens of V. wangii collected at Laojun Mountain are found growing on bark of Rhododendron sp. or on wood of Pinus at elevations ranging from 3400–3900 m. However, Violella wangii differs in its chemistry (atranorin and roccellic / angardianic acid), thallus morphology (white, granular corticate areoles, sorediate) and larger apothecia [(0.7 –) 1.3–2.6 (– 4.1) mm] (Fig. 3 A, B). V. fucata differs from V. yunnanensis in possessing a generally thin, effuse, sorediate thallus, apothecia rare and smaller ascospores [(38.5 ± 6.7 × 18.5 ± 3.3 μm, n = 24) vs (43 –) 50.4 ± 5.37 (– 63) × (23 –) 28.15 ± 3.5 (– 38) μm, n = 20)] (Spribille et al. 2011 b). Furthermore, Violella yunnanensis differs from Violella sinensis in its weakly warted thallus and larger ascospores.

Specimens examined.

China. Yunnan Prov.: • Diqing Tibetan Autonomous Prefecture, Deqin Co., on the way from Yubeng Upper Village to Glacier Lake beside the observation platform in Meili Snow Mountain National Park, 28°23'56.37"N, 98°46'8.97"E, 3506 m, on bark, 22 April 2023, L. Hu, C. J. Zhong & J. X. Wang. SDNU 20231997, 20232019, 20235026. • Lijiang, Yulong Co., Baisha Vi., Alpine Botanical Garden, 27°1'2.33"N, 100°10'27.11"E, 3708 m, on bark, 28 April 2023, L. Hu, C. J. Zhong & J. X. Wang. SDNU 20232618. • Yulong Co., next to Laojun Mountain Homestay Vi., 26°37'54.05"N, 99°43'37.23"E, 3821 m, on bark, 30 April 2023, L. Hu, C. J. Zhong & J. X. Wang. SDNU 20232874, 20232841, 20232885, 20232828, 20232875, 20232890, 20232882.