Lecidea sublaboriosa Z. J. Ren & Lu L. Zhang, 2025

Lecidea sublaboriosa Z. J. Ren & Lu L. Zhang sp. nov.

Fig. 3 View Figure 3

Diagnosis.

Similar to Lecidea laboriosa but with a brown to dark brown hypothecium and shorter ascospores ([6 –] 7–8.5 [– 10] × 2.5–3.5 [– 4] μm vs. [6 –] 8–12 [– 16] × [2 –] 2.5–4 [– 5] µm).

Type.

China • Tibet Prov., Angren Co., Sangsang vil. , 29°18'59.01"N, 87°02'02.97"E, alt. 4498 m, on rock, 19 Jul. 2019, L. S. Wang et al. 19-65307 ( KUN, holotype; GenBank PV 698372 ) GoogleMaps .

Etymology.

The specific epithet refers to the new species’ similarity to Lecidea laboriosa .

Description.

Thallus: endolithic to scarcely epilithic; prothallus: absent; surface: if present, whitish to cream-colored, rough, esorediate; medulla: white, I – or partially weakly I + violet; algal layer: not obvious; photobiont trebouxioid, cells (9 –) 10–13 (– 15) μm diam. Apothecia: abundant, sessile, lecideine, 0.65–1.5 mm diam.; disc: black, flat to convex, epruinose to faintly white pruinose; proper margin: black, regular or corrugated, occasionally becoming excluded in old apothecia. In section: exciple: black-brown outside, hyaline to light brown inside, with small crystals (POL +) dissolving in N and insoluble in K; epihymenium: black-green (N + violaceous, K –), 7.5–12.5 μm thick; hymenium: hyaline or slight blue-green, 30–40 μm tall; paraphyses: simple, unbranched, slightly enlarged at the apex, apical cells 2.5–3 (– 4) μm; subhymenium: hyaline to light brown, 12–20 μm thick; hypothecium: brown to dark brown; asci: clavate, Lecidea - type, 8 - spored; ascospores: hyaline, simple, ellipsoid, (6 –) 7–8.5 (– 10) × 2.5–3.5 (– 4) μm, length-width index: 1.8–2.5 (– 3.2) (n = 20). Conidiomata: not seen.

Chemistry.

Cortex and medulla K –, C –, KC –; 4 - O - demethylplanaic acid detected by TLC.

Additional specimens examined.

China • Tibet Prov., Zhongba Co., Larang Vil. , 29°47'20.00"N, 83°54'12.10"E, alt. 4652 m, on rock, 25 Jul. 2019, L. S. Wang et al. 19-64947 ( KUN); 19-65613 ( KUN) GoogleMaps . • Dazi Dist., Bangdui Vil. , 29°45'44.00"N, 91°25'29.28"E, alt. 3698 m, on siliceous rock, 16 Jul. 2019, L. S. Wang et al. 19-64619 ( KUN) GoogleMaps .

Distribution.

This species is found in the plateau sub-frigid, semi-arid climate zone of China, growing on exposed siliceous rocks.

Discussion.

We have conducted multiple phylogenetic tree reconstructions, in which Lecidea sublaboriosa is placed as a sister species to L. laboriosa Müll. Arg. is either weakly supported or unsupported. Despite this phylogenetic uncertainty, L. sublaboriosa exhibits a high degree of morphological and chemical similarity with L. laboriosa , including an endolithic to scarcely epilithic thallus, a green epihymenium, a low hymenium, and the presence of 4 - O - demethylplanaic acid. Additionally, it is morphologically similar to L. andersonii , L. auriculata Th. Fr. , L. diducens , and some specimens of L. polypycnidophora , in that they all either lack an epilithic thallus or, if one is present, it is poorly developed. All of the above species have been detected in the Qinghai-Tibetan Plateau; however, they differ in that Lecidea andersonii has larger ascospores ([8 –] 9–12 × 3.5–4.4 μm vs. [6 –] 7–8.5 [– 10] × 2.5–3.5 [– 4] μm) and an I + violet medulla; L. auriculata has an I + violet medulla and contains confluentic acid; L. diducens has a C + red exciple and contains 2 ’ - O - methylanziaic acid; L. laboriosa has larger ascospores ([6 –] 8–12 [– 16] × [2 –] 2.5–4 [– 5] µm vs. [6 –] 7–8.5 [– 10] × 2.5–3.5 [– 4] μm) and hyaline to light brown hypothecium; L. polypycnidophora has broader ascospores (6–8 × 3–4.5 μm vs. [6 –] 7–8.5 [– 10] × 2.5–3.5 [– 4] μm) and abundant pycnidia ( Inoue 1991; Hertel and Printzen 2004; Ruprecht et al. 2010; Fryday et al. 2024).