The holotype of this lichen was collected in the Southern Tablelands of New South Wales, specifically in the Badja State Forest, approximately 9 km (5.6 mi) northeast of Numeralla along the road to Jerangle, at an elevation of 1,095 m (3,593 ft).

The individual areoles are contiguous, angular, and irregularly shaped, ranging from 0.1 to 0.5 mm in width, typically with slightly raised edges.

They are lecideine in form, initially immersed but becoming broadly adnate, with a black, epruinose disc that is either plane or markedly convex.

While it shares some morphological traits with R. geminatum, such as the presence of rhizocarpic acid in the medulla, the latter has a darker, more robust thallus, larger apothecia, and primarily two-spored asci.

R. sulphurosum from north-western North America also features a yellow medulla, but differs in having peltate areoles with pale margins and larger, 3-septate to muriform ascospores.