Also found in: Dictionary, Thesaurus, Wikipedia.
a family of monoecious dicotyledonous plants containing the single genus Ceratophyllum. The plants are rootless perennial aquatic grasses with whorls of forked, dissected, sessile leaves. The tiny flowers are unisexual, solitary, and axillary. The calycine perianth consists of eight to 12 sections joined at the base. The fruit is a nut with a persistent thorny stem. Pollination occurs underwater.