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

Fig. 9

Etymology.

The epithet refers to the Chinese lichenologist Li-Song Wang, who collected the type specimen.

Diagnosis.

Thallus areolate without marginal lobes, upper surface white, flat; apothecia common, cryptolecanorine to lecanorine, disc black, pruinose, slightly concave to plane, often shallowly fissured at maturity; epihymenium N + weakly greenish to green, containing norstictic and connorstictic acids.

Holotype.

China • Xizang Autonomous Region: Shigatse Ci., Dingri Co., along road G 219 , 28°35'10.18"N, 87°03'43.62"E, alt. 4311 m, on rock, 06 June 2022, Li-Song Wang et al. 22-71215 ( KUN-L 85839 ) .

Description.

Thallus tightly adnate to the substrate, 1–4 mm thick, areolate without marginal lobes, spreading in the field up to 25 cm across, the collected specimen is fragmented, up to 4 cm across. Central areoles commonly rounded, (0.2 –) 0.5–1 (– 1.6) mm diameter, not constricted at base, interspaces between areoles 0.1–0.2 mm wide; marginal areoles rounded to slightly elongated, 0.8–1.2 × 0.5–1.2 mm. Upper surface flat, white and pruinose. Upper cortex paraplectenchymatous, 30–50 μm thick, inspersed with pale gray granules (soluble in K), uppermost part filled with dark brown granules (partly soluble in K), 20–30 μm thick; epinecral layer gray dark, 20–50 μm thick. Algal layer 75–100 μm thick, mostly continuous, occasionally interrupted by fungal tissue (10–20 μm wide); photobiont chlorococcoid, cells 8–20 µm in diameter. Medulla 0.5–2 mm high, filled with gray-black granules (generally insoluble in K). Lower cortex absent.

Apothecia predominantly immersed and cryptolecanorine, rarely emergent and lecanorine, numerous, 1 to 3 per areole, (0.1 –) 0.3–1 (– 1.5) mm wide, simple or grouped, orbicular to angular by pressure; disc black, pruinose, slightly concave to plane, often shallowly fissured at maturity; apothecial margin entire, pruinose, concolorous with thallus, absent when young, appearing and gradually receding as the apothecium develops, (0.05 –) 0.1–0.2 (– 0.25) mm wide. Exciple narrow, widening to 40–80 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 15–50 μm high, filled with brown to dark brown granules (dark soluble in K), N + weakly greenish to green; hymenium (75 –) 100–125 μm high, hyaline, I + pale blue to blue; subhymenial layers (40 –) 50–70 (– 100) μm high, hypothecium 20–60 μm, hyaline, I + blue; algal layer below the hypothecium sparse or absent; paraphyses simple, occasionally anastomosing, septate, submoniliform, with 1–3 (– 4) uppermost cells shorter and broader, 4–6 μm wide (basal cells ca. 2 μm wide); asci clavate, Aspicilia - type, hyaline, 8 - spored, 60–80 × 20–30 µm; ascospores simple, hyaline, broadly ellipsoid to ellipsoid, (10.0 -) 11.9–13.4 – 14.9 (- 17.0) × (7.0 -) 7.9–8.6 – 9.2 (- 10.0) µm (n = 89), l / w ratio (1.1 -) 1.4–1.6 – 1.8 (- 2.1), wall ca. 1 µm thick. Pycnidia few, punctiform, plane to slightly convex, 0.1–0.2 mm diameter; ostiole dark brown; conidia bacilliform, hyaline, 5–7 (– 9) × 1 µm.

Chemistry.

Cortex K + pale yellow, P –; medulla K + yellow to orange-red, P + yellow, C –, KC –. Norstictic acid and connorstictic acids detected in TLC.

Habitat and distribution.

Saxicolous. Currently only known in Xizang, China.

Notes.

Lobothallia controversa and L. cheresina resemble L. wangii but differ in having completely immersed apothecia and different secondary metabolites. Lobothallia controversa has two chemotypes ( Roux et al. 2016): chemotype controversa exhibits no reaction to standard reagents (K, C, KC, P, I) but produces terpenoids, while chemotype reagens shows K + and P + reactions due to the presence of stictic acid complex along with terpenoids. Lobothallia cheresina has three chemotypes ( Müller 1880; Roux 2012): chemotype cheresina lacks secondary metabolites; chemotype justii contains stictic acid as the main secondary metabolite; and chemotype microspora produces norstictic acid as the major compound. Lobothallia iqbalii and L. lacteola also possess a white, areolate thallus, and cryptolecanorine to lecanorine apothecia. However, Lobothallia iqbalii is distinguished by its plane to convex discs, raised and persistent apothecial margin, N – epihymenium, and absence of secondary metabolites or presence of only norstictic acid ( Zulfiqar et al. 2022, 2023). Lobothallia lacteola differs from L. wangii in its thinner thallus, plicate margins, and absence of connorstictic acid ( Paukov et al. 2019).

Additional specimens examined.

China • Xizang Autonomous Region: Shigatse Ci., Tingri Co., National Highway 219 , 28°35'10.18"N, 87°03'43.62"E, alt. 4311 m, on schist, 16 June 2022, Yan-Yun Zhang ZYY 22-324 ( KUN-L 81905 ), ZYY 22-331 ( KUN-L 81912 ), ZYY 22-334 ( KUN-L 81915 ) • Zhaguo Vi. : 28°35'25.56"N, 86°53'56.03"E, alt. 4292 m, on rock, 27 July 2019, Li-Song Wang et al. 19-65657 ( KUN-L 70164 ), 19-64063 ( KUN-L 68559 ) .

Figures

Figure 9. Lobothallia wangii (KUN-L 85839, holotype). A. Habit; B, C. Apothecia; D. Section of thallus (below in K reagent); E. Upper cortex and epinecral layer (LCB); F. Section of apothecium; G. Section of apothecium (in N reagent); H. Section of pycnidium; I. Ascus and ascospores; J. Paraphyses (LCB); K. Conidia. Scale bars: 1 mm (A); 0.2 mm (B, C); 100 µm (D, G); 20 µm (E, F, H); 10 µm (I); 5 µm (J, K).