Submersed, branching perennial aquatic herbs sometimes attached to the substrate by root-like branches. Leaves in whorls, finely divided and with fine teeth along the divisions, dying at the base of the stem as new growth emerges. Flowers unisexual, solitary, axillary, male and female flowers on alternate nodes, surrounded by bracts. Carpel 1. Ovary superior. Fruit a 1-seeded mostly spiny nut.

Common name derived from the translucent, brittle, antler-like leaves. Family known by the single genus Ceratophyllum and frequently grown in aquaria and pools as C. demersum L., Hornwort which has leaves that fork 1–2 times and ultimate segments with numerous marginal teeth. In nature Ceratophyllum generally floats in large masses just below the water surface and is frequently present in weedy proportions sometimes choking waterways. Recent evolutionary research suggests that the family was one of the first flowering plant families to arise.

Cuttings although in nature seed and detached winter buds act as propagules.

Leaves divided to 3 times and arranged in whorls along the stems. Vegetatively similar to the aquarium plants Myriophyllum, Milfoil, in the Haloragaceae which has simple or pinnately divided, non-toothed leaf divisions and Cabomba, Fanwort, (native of America and serious aquatic weed elsewhere) which has leaves of 2 different kinds that are opposite or whorled, at least the lower ones distinctly fan-like, stalked and with 3–7 branchings.

A cosmopolitan genus of 6 species; it occurs as a native in all states of Australia except Tasmania where it is regarded as secondary and designated a prohibited noxious weed.

Wilmot-Dear (1985), Les (1989).

Source: Spencer, R. (1997). Ceratophyllaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.

Updated by: Niels Klazenga, December 2017

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Ceratophyllanae
order      Ceratophyllales
Higher taxa
Subordinate taxa
genus        Ceratophyllum