Description: This rather small and insignificant Bacidia with a grey, green or fawn, soft, scurfy, granular-sorediate thallus and reddish-brown discs grows on sheltered calcareous rocks, mortar and on bark. A feature of this species is the rather discrete soralia. The outer edge of the exciple in squash is K+ purplish; there is no trace of blue-green pigment. The conidia are curved.

Key Identification Features:

• Thallus grey, green or fawn, soft-granular, the soralia discrete
• Exciple outer edge, K+ purple.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Bacidina caligans at iNaturalist World Species Observations database.