Stoneworts are submerged aquatic algae and are believed to be the closest relative of green land plants. They are multi-cellular and frequently encrusted with calcium carbonate deposits. Branched, with whorls of small branchlets at nodes.
Chlorophyll-using, found in fresh or brackish water. Approximately 33 different species occur in Britain and Ireland. Identified by Paul Green
Stonewort. The Burren, Co.Clare. July 2008