Scientific name: Ceratophyllum demersum L.
Common name: Hornwort
Description
Habit: A submerged aquatic, rootless perennial.
Stems: Branched, up to 1 m long.
Leaves: In whorls of 6-8, 1-2 cm long, deeply divided into narrow segments, finely toothed, regularly forked, rather rigid.
Flowers: Submerged, inconspicuous, solitary; perianth of numerous, narrow, free segments, green or purple; stamens 5-20.
Fruits: A black, ovoid nut, 4-5 mm, often with 2 long spines at the base; rarely produced.
Habitat: Pools, streams and lakes.
Distribution: Rare.
Native status: Native
Of conservation interest: No