Ceratophyllaceae Gray
Rootless, monoecious, submerged aquatic herbs, anchored by specialised branchlets. Stems long, slender, branched. Lvs in whorls of 3-10, dichotomously forked 1-4 times; segments denticulate, bristle-tipped. Fls small, solitary in lf axils. Perianth a single whorl of 8-12 linear segments. Stamens numerous; anthers sessile or subsessile, extrorse. Ovary superior, of 1 carpel with 1 pendulous ovule. Fr. a 1-seeded nut, often with 1-2 spines present at base; style persistent, spinous.
1 genus, c. 30 spp., cosmopolitan.