Lobothallia pulchra Lun Wang & Y. Y. Zhang, 2025

Wang, Lun, Feng, Yi-Shan, Wang, Li-Song, Wang, Xin-Yu & Zhang, Yan-Yun, 2025, An overview of the genus Lobothallia (lichenized Ascomycota, Megasporaceae) in China, MycoKeys 125, pp. 205-244 : 205-244

Lobothallia pulchra Lun Wang & Y. Y. Zhang sp. nov.

Fig. 6

Etymology.

The epithet refers to the beautiful morphology of the thallus of this species.

Diagnosis.

Thallus areolate with radiate lobes, upper surface white and pruinose; apothecia lecanorine, adnate and rounded, 1–2 apothecia per areole, apothecial margin distinct and persistent, disc plane to slightly convex, not to rarely with faint pruina, containing norstictic and stictic acids.

Holotype.

China • Xizang Autonomous Region: Shigatse Ci., Dingri Co., Zhaguo Vil. , 28°35'24.49"N, 86°53'58.22"E, elev. 4293 m, on rock, 27 July 2019, Li-Song Wang et al. 19-66027 ( KUN-L 70435 ) .

Description.

Thallus tightly adnate to the substrate, 0.3–2 mm thick, centrally areolate, marginally lobate. Areoles 0.5–1.2 mm wide, angular to rounded, not constricted at base, interspaces between areoles 0.05–0.1 mm wide. Lobes radiate, short, 1–2.5 mm long, base width (0.3 –) 0.6–0.8 (– 1) mm, apex width 0.6–2 mm. Upper surface moderately convex, white, partially pale brown on marginal lobes, pruinose. Upper cortex paraplectenchymatous, even, 30–40 μm thick, containing brown granules (soluble in K); epinecral layer gelatinous, 10–20 μm thick. Algal layer 125–150 μm high, discontinuous; photobiont chlorococcoid, cells 6–18 µm diameter. Medulla 0.3–0.6 mm thick, opaque, filled with gray-black granules (insoluble in K). Lower cortex absent.

Apothecia lecanorine, common, 1–2 per areole, simple to grouped in the center, orbicular to slightly angular by pressure from adjacent apothecia, (0.3 –) 0.6–2 mm diameter, initially immersed, later sessile, not to slightly constricted at base; disc plane, matt, brownish-black to black, epruinose or faintly pruinose, shallowly fissured when overmature; apothecial margin entire, concolorous with thallus, well-developed and persistent, (0.05 –) 0.1–0.2 (– 0.25) mm. Exciple narrow, widening to 70–80 μm in the uppermost part. Epithecium, hymenium and subhymenial layers combined 125–160 µm high; epithecium 5–15 µm high, epihymenium 12.5–20 μm high, filled with dark brown to brown granules (mostly soluble in K), N –; hymenium 90–100 μm high, hyaline, I + dark blue; subhymenial layers ca. 50 μm high, hyaline, I + dark blue; discontinuous algal layer beneath hypothecium; paraphyses simple, septate, submoniliform at the tips, 1–4 uppermost cells shorter and broader than basal cells, 3–5 μm wide (basal cells 2–3 μm wide); asci clavate, Aspicilia - type, hyaline, 8 - spored, 70–80 × 20–30 µm; ascospores simple, hyaline, ellipsoid to broadly ellipsoid, (10.0 -) 10.8–12.3 – 13.7 (- 16.0) × (8.0 -) 7.8–8.5 – 9.1 (- 10.0) µm (n = 30), l / w ratio (1.1 -) 1.3–1.5 – 1.7 (- 1.9), wall ca. 1 µm thick. Pycnidia few, punctiform, flat to slightly convex, 0.15–0.2 mm diameter; ostiole brownish black; conidia bacilliform, hyaline, 6–8 × 1 µm.

Chemistry.

Cortex K + pale yellow or K –, P –; medulla K + yellow to orange-red, P + yellow or orange-red, C –, KC – or KC + pale yellow; norstictic and stictic acids detected by TLC, some specimens additionally contain cryptostictic, connorstictic and constictic acids.

Habitat and distribution.

Saxicolous. Currently known from Xizang and Qinghai Provinces, China.

Notes.

Lobothallia pseudopruinosa and L. pruinosa resemble L. pulchra in having an areolate thallus with radiate lobes and a white pruinose surface, but differ in their indistinct apothecial margin, distinctly pruinose discs, and the absence of stictic acid ( Kou et al. 2013). Lobothallia wangii differs from L. pulchra in its predominantly cryptolecanorine apothecia, N + epihymenium, and the absence of both marginal lobes and stictic acid. Lobothallia pakistanica and L. pulvinata also have a white thallus with central areoles and marginal lobes, but differ from L. pulchra in their thinner thalli, apothecia that are not constricted at base, and in the lack of stictic acid ( Zulfiqar et al. 2022, 2023).

Additional specimens examined.

China • Xizang Autonomous Region: Tingri Co., Zhaguo Vi. , 28°35'24.49"N, 86°53'58.22"E, alt. 4256–4299 m, on rock, 27 July 2019, Li-Song Wang et al. 19-65686 ( KUN-L 70194 ), 19-65652 ( KUN-L 70159 ) • Dagze Co., Bangdui Vi , 29°44'06.51"N, 91°24'55.29"E, alt. 3700 m, on rock, 16 July 2019, Li-Song Wang et al. 19-64597 ( KUN-L 69093 ) • Qinghai: Yushu Tibetan Autonomous Prefecture, Zaduo Co., 32°52'43.64"N, 95°20'29.61"E, alt. 4074 m, on rock, 20 September 2020, Li-Song Wang et al. 20-67281 ( KUN-L 75458 ) • Ado Vi. , 32°52'43.35"N, 95°20'30.19"E, alt. 4080 m, on rock, 20 September 2020, Xin-Yu Wang et al. XY 20-3169 ( KUN-L 79525 ) .

Figures

Figure 6. Lobothallia pulchra (KUN-L 70435, holotype). A. Habitat; B. Thallus; C. Lobes; D. Apothecia; E. Vertical section of apothecium; F, G. Section of thallus (G in LCB); H. Vertical section of apothecium (LCB); I. Ascus; J. Paraphyses (LCB); K. Ascospores; L. Conidia (LCB). Scale bars: 1 mm (B); 0.5 mm (C); 0.2 mm (D); 100 µm (E, F, G); 50 µm (H); 5 µm (I, J, K, L).