[3] One of the traits is the absence of a vascular cambium, which is required to produce both xylem (wood) and phloem, which therefore are missing.

All of the species are rhizomatous aquatic herbs with a broad leaf base and large, showy flowers.

Several Cretaceous-age Cabombaceae genera are also known, including Scutifolium from Jordan, Pluricarpellatia from Brazil, and Brasenites from Kansas.

[12] The fossil genus Notonuphar, thought to be a close relative of the modern Nuphar, is known from Eocene-aged sediments from Seymour Island, Antarctica.

[14][15][16] The aquatic plant fossil Archaefructus from the Early Cretaceous of Liaoning, China possibly also belongs to this group.

Amborella Hydatellaceae Cabombaceae Nymphaeaceae Austrobaileyales magnoliids Chloranthales monocots Ceratophyllum eudicots This order was not part of the APG II system's 2003 plant classification (unchanged from the APG system of 1998), which instead had a broadly circumscribed family Nymphaeaceae (including Cabombaceae) unplaced in any order.