Description: This Arthonia is a lichenicolous species on the thallus of Schismatomma quercicola (described elsewhere). The thallus of the host can be checked with Pd which should turn it red. The discs of A. invadens are dark brown and star-shaped with elongated tails. Spores are two- to three-septate with the upper cell enlarged. It has been recorded from south-east Ireland.

Key Identification Features:

• Discs dark brown like stars with points trailing like ribbons; spores two- or three-septate
• On the thallus of Schismatomma quercicola; old woodlands.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Arthonia invadens at iNaturalist World Species Observations database.