A genus of mosses, which are usually aquatic. The stems are long and irregularly branched. Leaves are ovate or lanceolate, concave or plane, and nerveless. There are about 20 species, found mainly in northern temperate regions. Two species are found in Britain. F. antipyretica (willow moss) grows on wood or rocks in slow-moving rivers and streams, and in lakes and ponds. The shoots are long (up to 70 cm) and little branched; leaves are borne in 3 ranks, and each leaf is folded and has a sharp keel. F. squamosa lacks the keel on the leaves and is found in fast-moving, non-calcareous waters.
Subjects: Plant Sciences and Forestry.