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

Fig. 8

Etymology.

The epithet refers to the areoles with a constricted and stipitate base.

Diagnosis.

Thallus brown, thick, centrally areolate, areoles with a stipitate base, marginally lobate, margin of lobes free from the substrate with granular pruina on the upper surface; apothecia lecanorine, constricted at the base, disc with conspicuous white pruina, apothecial margin persistent, epruinose, brown to orange-brown; hymenium pale brown.

Holotype.

China • Xinjiang Uygur Autonomous Region: Hejing Co., along road G 218 , 42°54'22.90"N, 86°17'36.95"E, alt. 2228 m, on rock, 01 July 2022, Li-Song Wang et al. 22-72871 ( KUN-L 87358 ) .

Description.

Thallus relatively loosely attached to the substrate, up to 4–6 cm across, centrally areolate, 3–6 (– 8) mm thick, marginally lobate, (0.5 –) 1–2 mm thick, free from the substrate. Areoles angular ( 0.6–1.2 mm wide) to elongated (1.5–2 × 0.6–1 mm wide), base constricted into a stipe, up to 4 mm long, interspaces between areoles 0.1–0.3 mm wide. Lobes long, simple to 2–3 branched, apices slightly wider than base, 3–5 mm long, 0.6–1.5 mm wide at base, 0.6–2.5 mm wide at apex. Upper surface flat to slightly convex, matt, brown, thinly pruinose, granular pruina present on the margin of lobes. Upper cortex paraplectenchymatous, even, 40–50 μm thick, inspersed with brownish and gray granules (soluble in K); epinecral layer gelatinous, 10–15 μm thick. Algal layer 75–150 μm high, discontinuous; photobiont chlorococcoid, cells 10–25 µm diameter. Medulla 0.6–3 mm high, filled with gray-black granules (generally insoluble in K). Lower cortex absent.

Apothecia lecanorine, common, 1–2 per areole, simple to grouped, orbicular to angular by pressure, (0.3 –) 0.5–1.5 (– 1.8) mm wide, constricted at base in maturity; disc concave to plane, brown to black, conspicuously pruinose; apothecial margin entire, persistent, epruinose, brown to orange-brown, 0.1–0.25 (– 0.3) mm wide. Exciple narrow, widening to 60–80 μm in the uppermost part. Epithecium, hymenium and subhymenial layers combined 125–175 µm high; epithecium 5–15 µm high, with hyaline plate-like crystals; epihymenium 12.5–37.5 μm high, filled with dark brown granules (soluble in K), N –; hymenium 100–120 μm high, pale brown (soluble in K), I + dark blue; subhymenial layers 50–75 μm high, hypothecium 40–50 μm, pale brown (soluble in K), I + dark blue; algal layer below hypothecium sparse or absent; paraphyses simple, septate, submoniliform at the tips, with 2–4 uppermost cells shorter and broader than basal cells, 3–5 μm wide (basal cells ca. 2 μm wide); asci clavate, Aspicilia - type, hyaline, 8 - spored, 70–85 × 18–25 µm; ascospores simple, hyaline, broadly ellipsoid to ellipsoid, (9.0 -) 9.8–11.4 – 12.9 (- 15.0) × (7.0 -) 6.8–7.6 – 8.4 (- 11.0) µm (n = 30), l / w ratio (1.0 -) 1.3–1.5 – 1.7 (- 2.0), wall ca. 1 µm thick. Pycnidia punctiform, plane to slightly convex, 0.1–0.25 mm diameter; ostiole brown to dark brown; conidia bacilliform, hyaline, 4–6 × 1 µm.

Chemistry.

Cortex K + pale yellow, P –; medulla K + yellow, P + orange, C –, KC –; containing norstictic, stictic, cryptostictic and connorstictic acids.

Habitat and distribution.

Saxicolous. Currently only known from Xinjiang Province, China.

Notes.

Lobothallia praeradiosa resembles L. stipitata in having an areolate thallus with radiating lobes, a constricted apothecial base, orange-brown thallus and apothecial margins, and containing norstictic acid. However, the former differs in its epruinose disc, hyaline hymenium, and lack of stictic acid ( Kou et al. 2013; Paukov et al. 2019; Ryan 2004). Lobothallia semisterilis shares narrowly elongated lobes with granular pruina on the margins, but differs in its terricolous habitat, white to gray thallus, apothecia-like pycnidia, and absence of stictic acid ( Zhang et al. 2020).

Additional specimens examined.

China • Xinjiang Uygur Autonomous Region: Hejing Co., National Highway 218 , 42°54'22.90"N, 86°17'36.95"E, alt. 2228 m, on limestone, 1 July 2022, Yan-Yun Zhang ZYY 22-616 ( AHUB 00470 ), ZYY 22-617 ( KUN-L 82191 ) • Baluntai Town , 42°54'36.56"N, 86°17'02.47"E, alt. 2171 m, on rock, 1 July 2022, Xin-Yu Wang and Min Ai XY 22-887 ( KUN-L 84705 ) .

Figures

Figure 8. Lobothallia stipitata (KUN-L 87358, holotype). A. Thallus; B. Profile of thallus; C. Stipe; D. Lobes; E. Apothecia; F. Pycnidium; G, H. Section of thallus (H in K reagent); I. Vertical section of apothecium (LCB); J. Vertical section of apothecium; K. Upper cortex and epinecral layer (LCB); L. Ascus; M. Paraphyses (LCB); N. Ascospores; O. Conidia. Scale bars: 2 mm (A); 1 mm (B, C); 0.5 mm (D); 0.2 mm (E, F); 100 µm (G, H); 50 µm (I, J); 20 µm (K); 10 µm (L, M, N, O).