Description: The exotic-looking, crustose to scaly thalli of grey, clustered isidia (thallus pegs) which are much branched like a marine coral, bears numerous scattered discs also fringed with isidia. The thallus is K+ yellow. It is rare in Ireland and present only in Counties Kerry and Cork. It grows best on the mossy or Frullania-rich bark of old oak trees that are warmed by the sun.

Key Identification Features:

• Thallus grey, of peg-like isidia much branched like an underwater coral
• Often with discs isidiate at the fringes; sunny, bryophyte-rich trees in the old oak woodlands of the south-west.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Rinodina isidioides at iNaturalist World Species Observations database.