Fig. 4

Concatenated Trebouxia phylogeny covering the ITS1, 5.8S, ITS2 and rbcL gene regions of sequences derived from direct sequencing of lichen material and isolates. A four major Trebouxia clades A (green), I (blue), C (orange) and S (red) after [50] and their assigned predominant pyrenoid and chloroplast structure reproduced after Bordenave et al. [48]. B, C phylogenetic reconstruction of the I clade (blue) and the A clade (green), respectively. Novel lineages are highlighted in color while already detected lineages are marked in gray. Stars mark potential species candidates for each novel lineage based on its phylogenetic positioning and morphological traits. Bold sequences without color boxes are derived from Trebouxia photobionts of epiphytic lichens sharing the same habitat but are not part of the grit crust. Orange circles indicate the number of the genus the corresponding mycobiont can be assigned to referring to Figs. 5, 6. Branches supported > 80% by Bayesian Inference (BI) and Maximum Likelihood bootstrap (ML) are labeled by an asterisk