Description: This small, crustose lichen which is orange, creamy yellow or green with pink-orange fruits is abundant on boulders in unpolluted, fast-flowing streams and rivers. The colour of both thallus and discs varies in intensity and shade. It can be splashed onto the stonework of bridges in spate. Equally, it is common on acidic seepage rocks in the uplands. It is widespread in suitable siliceous habitats, especially in western Ireland.

Key Identification Features:

• Variably cream to orange thallus with pink-orange fruits
• A character-species of fast-flowing streams and rivers where it can occur in all zones from the submerged to the terrestrial; search for it on midstream boulders especially.

Original text submitted by Simon Davey

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

iNaturalist: Hymenelia lacustris at iNaturalist World Species Observations database.