The R. atroflavescens thalli are 2–5 cm in diameter. The areoles are densely packed and form almost continuous crusts. The prothallus represents an important distinguishing character. Unlike most other Rhizocarpon species, it is grey to whitish. The areoles are pale yellow to yellow-white.
The species typically occurs on slightly calcareous rock substrates in submontane to montane areas. It is quite common in the mountains of the continental parts of Europe. In the Czech Republic, it is so far known from the Velká kotlina glacial cirque in the Hrubý Jeseník Mts.
Literature: Bouda F. (2017): Nové druhy žluté skupiny rodu Rhizocarpon v České republice. – Bryonora 59: 24–29.
taxonomic classification:Ascomycota → Lecanoromycetes → Rhizocarpales → Rhizocarpaceae → Rhizocarpon
Red List (Malíček 2023):C1 – critically endangered
Occurrence in the Czech Republic
All records: 1, confirmed 1. One click on a selected square displays particular record(s), including their source(s).