Lepraria is a widespread lichen genus containing c. 80 species. The species reproduce only asexually, but still were able to speciate. Lepraria species are known for their specificity towards the green algal photobiont Asterochloris, which is one of the most common genera of green, coccoid photobionts found in lichens. Only few data have been reported about relationships between photobionts and mycobionts of Lepraria. It was proven in previous works that partnership between Lepraria and Asterochloris broke down over evolutionary time and that the symbiont-switching occurred in their evolution. Limited number studies which cover photobiont diversity in species of the genus Lepraria are available, therefore, it is necessary to study the diversity of photobionts in those members of the genus Lepraria occurring in different habitats. We aim to answer three particular questions: Do different species of Lepraria share the same Asterochloris species/OTUs in the same habitat conditions (in forests, roadsides)? Do the photobiont switch and horizontal transfer occur between different taxa of Lepraria and lead to a better acclimatization of lichens to environmental conditions? Does the same species of Lepraria associate with only single or different Asterochloris OTU in different geographical regions? The so far obtained data suggest that some Lepraria species may be less specific to photobionts and this may allow them to grow in different light conditions, while the others (L. finkii) are associated with one type of photobiont, which perhaps has narrower ecological amplitude; however it requires further studies. There is no correlation between the photobionts and the type of substrate (soil, rocks, bark of various tree species), but sequences obtained from Asterochloris of Lepraria from Italy seem to show that the occurrence of this type of photobiont may be related to the presence of calcium carbonate in the substrate as all samples were collected from calcareous rocks.