Description: This rock-inhabiting, crustose lichen is virtually identical to B. aethelea (described elsewhere) but with a tiny, cracked thallus that is more or less white in colour. It is a coastal species that is usually associated with rocky places close to the sea. It is relatively common in suitable habitats in Ireland, but unlike Buellia aethelea tests K+ yellow not K+ yellow to red. Present in most coastal districts of Ireland.

Key Identification Features:

• Very close to Buellia aethelea, and may also be confused with some small Rhizocarpon species. The almost-white thallus helps to suggest this species, being much paler than that of Buellia aethelea which is brown-grey (never white)
• Both species are K+ yellow, but in the case of Buellia stellulata, the yellow colour change progresses through to red.

Original text submitted by Simon Davey

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

iNaturalist: Buellia stellulata at iNaturalist World Species Observations database.