Action Plan: Violet Crystalwort

Violet Crystalwort (Riccia huebeneriana) is a small liverwort which grows on nutrient-poor mud at the edge of large ponds, lakes, reservoirs and rivers. It appears to favour locations that are exposed following dry summers, but are under water during the winter. Its appearance depends largely on environmental conditions. In drought years there can be very large populations, but at other times the species often lies dormant below water. Disturbance to the mud on which the organism grows by cattle trampling may have implications on its continued success.

In Britain, this species has been recorded from over 20 widely scattered sites in Cornwall, Dorset, East and West Sussex, Surrey, Powys, Ceredigion, Anglesey, Cheshire, North Yorkshire and Argyll & Bute. However, it has not been recorded at many of these localities since 1970. In Northumberland violet crystalwort is found at one location in the district of Tynedale. It is difficult to know whether this is a true reflection of its status in the county due to its erratic population fluctuations and life-cycle. Violet crystalwort is provisionally classified as Vulnerable in Great Britain.