Thallus absent; species not lichenized, growing in the thallus Diploschistes spp. – Apothecia up to 0.8 mm diam., black, epruinose, orbicular or somewhat irregular, weakly to strongly convex, soon becoming immarginate; excipulum poorly developed; hypothecium dark brown, K–; hymenium pale brown to colorless; epihymenium dark brown, K+ red; a few scattered crystals in the apothecia; ascospores 8 per ascus, (1–) 3-septate (–submuriform), dark brown, 15–22 × 7–9 µm. – Conidiomata not seen.
Growing parasitic in the thallus of Diploschistes spp. on calciferous soil in open, exposed habitats; very rare (Vågå).
The species is the only non-lichenized Rhizocarpon in Norway.