General description:- Annual or perennial rootless herbs with horizontal stems and erect racemose inflorescences; terrestrial in damp places, with usually inconspicuous simple leaves, or aquatic with numerous conspicuous leaves which are divided into linear to filiform segments;
Leaves:- Bearing small bladders which trap minute organisms.
Flowers:- Calyx 2-lipped, divided almost to the base, usually accrescent; corolla 2-lipped, yellow; lower lip more or less spurred, with a gibbous palate; upper lip usually smaller.
Fruit:- Capsule usually globose, circumscissile, indehiscent or dehiscing by pores or slits. Seeds usually many.
Key features:-
1) Leaves divided into filiform lobes, alternate
The genus is predominantly tropical and most of the species native in Europe are atypical in the development of winter buds (turions). The vegetative parts are usually very variable and the identification of non-flowering material is often impossible; many of the published records are, therefore, open to doubt.