Description: In thallus colour and general appearance, P. monogona is identical to P. excludens (described elsewhere), but is entirely without soredia and isidia. It has an abundance of fertile warts (which contain the discs) frosted over with white pruina. The thallus is K+ red. In Ireland, this distinctive crustose species is very rare, being confined to sunny, coastal rocks in Counties Kerry and Cork.

Key Identification Features:

• Like P. excludens but differing in the absence of soralia and isidia and with abundance of fertile warts with frosted discs
• Thallus K+ red.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lepra monogona at iNaturalist World Species Observations database.