Lobothallia brachyloba Paukov & I. V. Frolov

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 brachyloba Paukov & I. V. Frolov , Lichenologist 51 (4): 306 (2019).

Fig. 10

Description.

Thallus areolate with lobate margin, tightly adnate to the substrate, up to 3 cm across, 0.6–2 mm thick. Areoles (0.5 –) 0.8–1.5 (– 2) mm wide, irregular to suborbicular, not constricted at base, interspaces between areoles mostly 0.2–0.4 mm wide. Lobes short, simple to 2–3 branched, 2–3 mm long, 0.6–1.5 mm wide at the base, 1–3 mm wide at the apex, mostly 0.6–0.8 mm thick. Upper surface flat to slightly convex, light gray with brownish tinge, thinly pruinose. Upper cortex paraplectenchymatous, even, 30–40 μm thick, with brown granules (soluble in K); epinecral layer 5–20 µm thick, with brown to black granules (insoluble in K). Algal layer 100–125 (– 200) µm thick, discontinuous; photobiont chlorococcoid, cells 8–18 µm diameter. Medulla 0.4–1.6 (– 2) mm high, filled with gray-black granules. Lower cortex absent.

Apothecia cryptolecanorine (rarely elevated as lecanorine, not constricted at base), numerous, 1–8 per areole, orbicular to slightly angular, (0.1 –) 0.2–0.7 (– 1) mm diameter; disc slightly concave to flat, black, matt, epruinose to faintly pruinose; apothecial margin usually indistinct (when lecanorine, slightly elevated, 0.05–0.2 mm wide). Exciple narrow, widening to 20–30 μm in the uppermost part. Epithecium, hymenium and subhymenial layers combined 175–225 µm high; epithecium 5–15 µm high; epihymenium 15–40 μm high, with brown dark granules (mostly soluble in K), N-; hymenium 120–140 µm high, hyaline, I + weakly bluish; subhymenial layers 60–75 μm high, hyaline, I + blue; algal layer beneath hypothecium discontinuous; paraphyses simple, septate, submoniliform at the tips, with 2–3 uppermost cells shorter and wider than the basal cells, 3–5 (– 6) μm wide (basal cells ca. 2 μm wide); asci clavate, Aspicilia - type, hyaline, 8 - spored, 60–70 × 15–22 µm; ascospores simple, hyaline, broadly ellipsoid, (9.0 -) 9.9–10.8 – 11.7 (- 12.0) × (7.0 -) 7.6–8.2 – 8.9 (- 10.0) µm (n = 41), l / w ratio (1.1 -) 1.2–1.3 – 1.4 (- 1.6), wall ca. 1 µm thick. Pycnidia few, punctiform, plane to slightly convex, 0.05–0.2 mm diameter, occasionally elongate, 0.2–0.4 × 0.05–0.1 mm; ostioles dark brown; conidia bacilliform, hyaline, 5–6 × 1–1.5 µm.

Chemistry.

Cortex K + yellow to orange-red, P + pale yellow; medulla K + yellow to red, P + yellow; containing norstictic acid.

Habitat and distribution.

Saxicolous. Currently known from the Altai mountains (Republic of Altai, Russia) and the Xinjiang Uygur Autonomous Region ( China).

Notes.

Lobothallia brachyloba is characterized by the areolate thallus with short marginal lobes, the light gray upper surface, the predominantly cryptolecanorine apothecia (1–8 per areole), and the presence of norstictic acid. Lobothallia crassimarginata resembles L. brachyloba in its gray areolate thallus, short marginal lobes and cryptolecanorine apothecia, but differs in typically bearing only one apothecium per areole, possessing a thick apothecial margin, and containing stictic acid ( Kou et al. 2013; Paukov et al. 2019). Lobothallia benzilanensis shares the gray thallus and presence of norstictic acid with L. brachyloba , but can be distinguished by its dispersed to continuous thallus lacking marginal lobes and its fewer apothecia per areole.

Specimens examined.

China • Xinjiang Uygur Autonomous Region: Xinyuan Co., Nalati Town , 43°16'14.26"N, 84°30'08.89"E, alt. 1885 m, on limestone, 1 July 2022, Li-Song Wang et al. 22-72815 ( KUN-L 87302 ) .

Figures

Figure 10. Lobothallia brachyloba (22-72815, KUN-L). A. Thallus; B. Apothecia; C. Lobes; D. Section of thallus; E. Upper cortex and algal layer (LCB); F. Section of small apothecium and pycnidium; G. Section of apothecium; H. Section of apothecium (LCB); I. Asci and ascospores (in K); J. Conidia; K. Paraphyses (in K). Scale bars: 1 mm (A); 0.5 mm (C); 200 µm (B); 100 µm (F); 50 µm (D, G, H); 20 µm (E); 5 µm (I, J, K).