## 3 Results
### Taxonomy
Xizang Prov., Linzhi, Nyingchi Seixula Mountain G318 Roadside, 28 June 2021, CMY-42. Sichuan Prov., Liangshan Yi Autonomous Prefecture, Muli Co., 27\({}^{\circ}\)43\({}^{\prime}\)30.93\({}^{\prime\prime}\) N, 101\({}^{\circ}\)14\({}^{\prime}\)11.34\({}^{\prime\prime}\) E, Alt. 3070 m, 11 September 2021, [PERSON] et al., 21-70424; Jiulong Co., Wuxuhai Lake, 29\({}^{\circ}\)09\({}^{\prime}\)06.00\({}^{\prime\prime}\) N, 101\({}^{\circ}\)24\({}^{\prime}\)42.99\({}^{\prime\prime}\) E, Alt. 3722 m, 9 June 2023, [PERSON] et al., 23-75118, 23-75119, 23-75121, 23-75122, 23-75122; Heishui Co., 32\({}^{\circ}\)13\({}^{\prime}\)57.72\({}^{\prime\prime}\) N, 102\({}^{\circ}\)36\({}^{\prime}\)21.75\({}^{\prime\prime}\) E, Alt. 3956 m, 4 September 2020, [PERSON] et al., XY20-399. Gansu Prov., Luqu Co., 34\({}^{\circ}\)08\({}^{\prime}\)23.63\({}^{\prime\prime}\) N, 102\({}^{\circ}\)11\({}^{\prime}\)55.61\({}^{\prime\prime}\) E, Alt. 3584 m, 9 July 2022, [PERSON] et al., XY22-1164. Austria, Salzburg, Lungau Eastern Alps, Niedere Tauern, Schladminger Tauern, Wei&Spriachtal NW of the village Mariapfarfar, a short distance from Lahnbrucke, 47\({}^{\circ}\)13\({}^{\prime}\)18\({}^{\prime\prime}\) N, 13\({}^{\circ}\)39\({}^{\prime}\)24\({}^{\prime\prime}\) E, Alt. 1280 m, 3 September 2019, [PERSON], ZYY-126. _Pseudosolarina tenuior_ [PERSON] and [PERSON], sp. nov. **Figure**12  
Fungal Names: FN 572278  
Type: China, Yunnan Prov., Shangrila city, Birong Valley, 26\({}^{\circ}\)39\({}^{\prime}\)05.36\({}^{\prime\prime}\) N, 99\({}^{\circ}\)44\({}^{\prime}\)15.57\({}^{\prime\prime}\) E, Alt. 3406 m, 15 July 2023, [PERSON] et al., 23-75283 (Holotype KUN)  
Etymology: Referring to its thin thallus and photobiont layer. Diagnosis: This species contains a single photobiont layer with both cyanobacterial and chlorophyte cells. It has the same four secondary metabolites as _P. simensis_, but _P. simensis_ has a thicker photobiont layer: more than 70 um in thallus and more than 60 um in  
Figure 11: _Pseudosolarina spongisoa_, (**A**: [PERSON] et al. 24-76099 KUN, **B**–**E**: [PERSON] et al. 23-75119 KUN); (**A**), habit of _P. spongisoa_; (**B**), apothecium; (**C**), white lower surface with brownish momentum; (**D**), transversal sections of the apothecium; (**E**), ascus. Scale bars: 2 mm (**B**); 1 mm (**C**); 200 μm (**D**); 40 μm (**E**). apothecia. _P. tenuior_ has a thinner photobiont layer: less than 60 \(\upmu\)m in thallus and less than 30 \(\upmu\)m in apothecia. Description: Thallus: large foliose, fragile, dorsiventral, heteromerous, lobate, 3-7 cm in diam. ; Lobes: rounded, 3-18 mm; Upper surface: green-gray when wet, gray-brown when dry, rare prunose on the margin; Upper cortex: parapelectenchymatous, colorless, 30-80 \(\upmu\)m thick; Medulla: 200-270 \(\upmu\)m thick; Photobiont: _Asterochloris_ and _Nostoc_, in a single photobiont layer, measured 20-60 \(\upmu\)m, photobiont layer in apothecium measuring 12-30 \(\upmu\)m; Lower cortex: lacking; Lower surface: pale to brown, indistinctly veined, tomentose, without cephalodia, with clusters of simple or branched rhizines; Apothecia: large, rounded, irregularly scattered, sunk in depressions in the upper surface, red-brown to black, slightly concave, thalline margin absent; Ascci: clavate, _Peltigera_-type, 4-spored; Ascospores: red-brown or dark brown, 1-septate with a median constriction, ellipsoid to fusiform, wall non-uniformly thickened, surface ornamented with broad reticulating ridges and irregular lacunae, dimensions: 40-55 \(\times\) 18-23 \(\upmu\)m.  
Figure 12: _Pseudosolorina tenuior_ ([PERSON] et al. 23-75283 KUN); (**A**), habit of _P. tenuior_; (**B**), white lower surface with brownish tometum and rhizines; (**C**), apothecia; (**D**), transversal sections of the thallus; (**E**), transversal sections of the apothecium; (**F**), ascus. Scale bars: 5 mm (**B**); 2 mm (**C**); 100 \(\upmu\)m (**D**); 200 \(\upmu\)m (**E**); 40 \(\upmu\)m (**F**).