Lecidea flavothallia C. X. Wang & Lu L. Zhang sp. nov.

Fig. 2

Diagnosis.

Similar to Lecidea truckeei but with orange thallus and shorter conidia ([6 –] 7–9 [– 10.5] × 1 μm vs. [10 –] 11.5–15 [– 18] × 1.2 μm).

Type.

China, • Tibet Prov., Lazi Co., Xiqin vil., 29°04'24.14"N, 87°58'35.83"E, alt. 4492 m, on soil, 18 Jul. 2019, L. S. Wang et al. 19-63574 (KUN, holotype; GenBank MW 443058).

Etymology.

The epithet “ flavothallia ” refers to the orange thallus.

Description.

Thallus: areolate, flat to bullate or lobate; prothallus: indistinguishable; areoles: dispersed, flat to convex, up to 2 mm in diam.; regular to irregular, angular to round in outline, with a whitish margin, esorediate; upper surface: shiny, (usually) yellowish orange to orange, occasionally with white or gray patches; cortex: 110–160 (– 220) μm thick; medulla: white, I –; algal layer: (60 –) 70–100 (– 150) μm thick; photobiont trebouxioid, cells (6 –) 7–10.5 (– 13) μm diam. Apothecia: abundant, subimmersed to sessile, lecideine, (0.6 –) 1.0–1.5 (– 2.0) mm diam.; disc: black, flat to convex, epruinose to faintly white pruinose; proper margin: black, prominent when young, occasionally becoming excluded in old apothecia. In section: exciple: black-brown outside, unpigmented inside, with small crystals (POL +) dissolving in N and insoluble in K; epihymenium: black-green to olive-green (N + red-brown with a faint purple, K –), 10–15 μm thick; hymenium: hyaline or slight green, 40–60 μm tall; paraphyses: simple, occasionally scarcely branched and anastomosing; subhymenium: hyaline, 15–20 μm thick; hypothecium: brown, red-brown to dark brown; asci: clavate, Lecidea - type, 8 - spored; ascospores: hyaline, simple, ellipsoid, (7 –) 8–9 (– 12) × 3.5–5 μm, length-width index: 1.8–2.2 (– 2.5) (n = 20). Conidiomata: immersed, graphidoid; conidia: bacilliform, (6 –) 7–9 (– 10.5) × 1 μm.

Chemistry.

Cortex and medulla K + yellow, C –, KC –; schizopeltic acid detected by TLC.

Additional specimens examined.

China • Tibet Prov., Lazi Co., Xiqin vil., 29°04'18.92"N, 87°58'37.49"E, alt. 4536 m, on soil, 18 Jul. 2019, L. S. Wang et al. 19-63591 (KUN); 19-65264 (KUN). • Angren Co., Kerangla vil., 29°19'01.67"N, 87°01'58.50"E, alt. 4530 m, on siliceous rock, 19 Jul. 2019, L. S. Wang et al. 19-63636 (KUN). • Dingri Co., Zhaguo vil., 28°35'09.72"N, 87°03'44.35"E, alt. 4316 m, on siliceous rock, 16 Jun. 2022, L. S. Wang et al. 22-71230 (KUN). • Jilong Co., Zheba vil., 29°17'25.50"N, 85°14'52.99"E, alt. 4555 m, on siliceous rock, 17 Jun. 2022, L. S. Wang et al. 22-71328 (KUN); • 29°17'24.62"N, 85°14'53.17"E, alt. 4571 m, on siliceous rock, 17 Jun. 2022, L. S. Wang et al. 22-71332 (KUN). • Yunnan Prov., Deqin Co., Baima Snow Mountain, 28°20'513"N, 99°03'984"E, alt. 4320 m, on soil, 28 Aug. 2006, L. S. Wang, Oh Soon-Ok & Niu Dong-ling. 06-26744 (KUN).

Distribution.

Currently, this species is only found on the Qinghai-Tibetan Plateau of China, growing on exposed rocks and occasionally on alpine meadow permafrost soil, between altitudes of 4,000 and 5,000 m.

Discussion.

The species has the general appearance of a member of the Lecidea atrobrunnea group, but the I – medulla and short conidia indicate otherwise. Molecular data indicate that it belongs to the L. auriculata group, with which it shares the dark hypothecium, low hymenium, narrow ascospores, and graphidioid conidiomata, but that it differs from other members of this group by the atrobrunnea - type thallus containing schizopeltic acid. Other Lecidea species with schizopeltic acid include L. cinerata Zahlbr., L. hassei Zahlbr., L. mannii Tuck., and L. truckeei Herre, but L. cinerata has larger ascospores (13–16 × 4.2–6.3 µm vs. [7 –] 8–9 [– 12] × 3.5–5 μm) and a C + red exciple (lecanoric acid vs. schizopeltic acid); L. hassei has an endolithic thallus and a brownish opaque exciple; L. mannii has a black prothallus, larger ascospores (10–15 × 5–6.7 µm vs. [7 –] 8–9 [– 12] × 3.5–5 μm), and gyrophoric acid (C + red); and L. truckeei has a dark reddish brown thallus and an I + intensely violet medulla (Herre 1911; Hertel and Printzen 2004; Lendemer and Knudsen 2007; Fryday and Hertel 2014). Additionally, Lecidea flavothallia and L. poeltii Hertel share similar characteristics, both possessing a shiny, well-developed thallus, a green epihymenium, a low hymenium, and a dark hypothecium, with distributions in the Himalayan region. However, L. poeltii differs in having a brown thallus, I + medulla, and larger mature spores (11–16 × 4.5–7 µm vs. [7 –] 8–9 [– 12] × 3.5–5 μm) (Hertel 1975, 1977 a).