Description: This crustose species consisting of brown squamules, and growing on stabilised soil close to the sea is thought by some to be a mere ecotype of Acarospora smaragdula. It is almost certainly under recorded in Ireland, and should be looked for on stable mud cliffs

Key Identification Features:

• The habitat and pale brown to reddish brown squamules should strongly suggest this species. The K+ red reaction should help to confirm it, but it is extremely unlikely that any other species of Acarospora will occur in the same habitat.
• There are squamulose species of Catapyrenium and Endocarpon pusillum that appear similar, but they do not have the large number of spores per ascus typical of Acarospora species.

Original text submitted by Simon Davey

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

iNaturalist: Trimmatothelopsis benedarensis at iNaturalist World Species Observations database.