A family of aquatic plants in which the stems are filiform, and leaves are in opposite pairs, entire, and exstipulate. The flowers are tiny, monoecious, borne in leaf axils, and without a perianth. There is 1 stamen, the ovary is 4-celled and 4-lobed, there are 2 long styles, and the fruit consists of 4 tiny drupes. There is 1 genus, Callitriche, with 17 species, of cosmopolitan distribution.
Subjects: Plant Sciences and Forestry.