## 4 Conclusions  
The revised circumscription of _Solarina_ now comprises two distinct species, _S. crocea_ and _S. crocoides_, which are distinguished by the unique characteristics of their thallus, photobiont layers, and chemistry. Specifically, _S. crocea_ can be identified by its smooth upper surface with apothecia and the presence of two photobiont layers. _S. crocoides_ is characterized by dark granules along the thallus margin and only a single photobiont layer containing both cyanobacteria and chlorophyte cells. No apothecia have been observed. These two species share similar secondary metabolites, but _S. crocea_ contains gyrophoric acid, which is absent in _S. crocoides_. Species within the new genus _Pseudosolarina_ can be categorized into three distinct groups based on characteristics, including color and size of their thalli and formation of the photobiont layer. The first group, _P. hepatizon, P. simensis_, and _P. tenuior_ comprises species with greyish-brown upper surfaces and a single photobiont layer containing both cyanobacteria and chlorophytes. _P. hepatizon_ differs from the other two species by its lack of secondary metabolites. _P. simensis_ and _P. tenuior_ both contain gyrophoric acid, methyl gyrophorate, tenuiorin, and 2\({}^{\prime}\)-\(O\)-methyltenuiorin. _P. simensis_ differs from _P. tenuior_ by the thickness of its photobiont layer (70-150 \(\upmu\)m) relative to _P. tenuior_ (20-60 \(\upmu\)m). The second group features species with green upper surfaces, relatively large thalli (2-5 cm in diam. ), and possession of a single green photobiont layer containing solely chlorophytes. This group consists of two species: _P. parmigera_ and _P. saccata. P. parmigera_ exhibits a more prunose upper surface without external cephalodia, whereas _P. saccata_ is rarely prunose and exhibits external cephalodia on the upper surface. The third group comprises three species with relatively small thalli (<2 cm in diam.). Thalli of _P. spongiosa_ form only a small circle around the apothecium. The most significant distinction between the three species is their number of ascospores; specimens of _P. bispora_ have two spores, _P. bispora_ var. _monospora_ has one large spore, and _P. spongiosa_ has four spores. Key to species of _Solarina_ and _Pseudosolarina_  
1a. Lower surface bright orange, containing solorinic acid  
2  
and averantin  
1b. Lower surface white or pale brown, without solorinic  
3  
acid and averantin  
2a. Thallus with smooth margin, contains two separate  
_S. crocea_  
photobiont layers  
2b. Thallus with sorediate margin, contains a single  
_S. crocoides_  
photobiont layer  
3a. Upper surface gray-brown, with single photobiont  
layer containing cyanobacteria and chlorophytes  
3b. Upper surface apple green, with single photobiont  
layer containing chlorophytes  
4a. Lacking secondary metabolites  
_P. hepatizon_  
4b. Containing secondary metabolites  
5a. Photobiont layer 20-60 \(\upmu\)m in thallus and 12-40 \(\upmu\)m  
_P. tentioir_  
in apothecium  
5b. Photobiont layer 70-150 \(\upmu\)m in thallus and 60-100 \(\upmu\)m  
_P. simensis_  
in apothecium  
6a. Thallus well-developed, 2-6 cm in diam. 7
6b. Thallus small, less than 2 cm in diam. 7a. Upper surface proinose, without external cephalodia  
_P. parmigera_  
7b. Upper surface rarely proinose, with external cephalodia  
_P. saccata_  
8a. Thallus less than 0.7 cm in diam., asci 4-spored  
_P. spongiosa_  
8b. Thallus 1-2 cm in diam., asci (1-)2-spored  
9a. Asci 1-spored  
_P. bispora_  
9b. Asci 2-spored  
**Author Contributions:** Conceptualization, L.W. and Y.Z. ; Methodology, M.A. and R.F. ; Investigation, Y.G., J.J. and S.Z. ; Resources, W.M. ; Writing--original draft, T.Z. ; Writing--review & editing, F.R.W. and X.W. All authors have read and agreed to the published version of the manuscript.