Description: The thallus of this species is pale and thin so it is just as well that it has the distinctive habitat of periodically flushed, semi-embedded pebbles and stones. A favourite place for it is alongside tracks by woodlands. It is a pioneer coloniser of damp siliceous rock fragments like Trapelia coarctata and Ionaspis lacustris. The tiny convex discs (0.15–0.4mm diam.) range from yellow to orange-brown. In Ireland, the species is extremely rare.

Key Identification Features:

• Thin skin of thallus with tiny convex yellow to orange discs
• Grows on the damp sides of half-buried pebbles on the slopes of moorland tracks regularly flushed with seepage water.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Micarea lithinella at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Micarea lithinella at iNaturalist World Species Observations database.