Description: This aquatic, crustose lichen is a familiar sight on permanently submerged bedrock, boulders or stones in streams, rivers and loughs. The thin, blackish thallus is sprinkled with low, cone-like projections: the spherical discs (perithecia). Examination of the spores show them to be small (about 9 x 6/7&

371;m), simple (without partitions) and broadly ellipsoid. The similar V. rheitrophila is black-flecked, the freckles lying like bits of shrapnel in the body of the thallus. Thinly scattered in Ireland.

Key Identification Features:

• Thin, blackish thallus, cone-shaped perithecia and small, broadly ellipsoid spores
• In the submerged zone of streams and rivers.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Verrucaria aquatilis at iNaturalist World Species Observations database.