Verrucaria aquatilis

The thallus of this aquatic lichen is grey-brown to dark green and forms a thin and smooth crust. Many black warts (perithecia) are scattered over the surface.

A lichen of freshwater habitats where it can be found submerged and normally on siliceous (acid) rocks.

All year round

An early coloniser of suitable areas.

Widespread, but with records suggesting a mainly northerly and westerly distribution in Britain. It is the most common of the freshwater Verrucaria species.

Occasional in Leicestershire and Rutland.