Upright herbaceous plant up to 1.7 m high, glabrous and glaucous. Alternate, oblong to obovate leaves up to 35 cm, tripinnate with the last filiform segments; petiole pods 1-3 cm long. Inflorescences with terminal and lateral umbels; numerous flowers with yellow petals. Fruit ovate-elliptic, glabrous, up to 4 mm long, compressed dorsally, narrowly winged ribs, the 2 lateral ones are broader.

This species is often confused with Foeniculum vulgare, which has a longer petiole pod and all the ribs of the fruit are the same.

Annual plant, very aromatic, erect, up to 2 m in height, covered with long hairs. Alternate or opposite bipinnatifid leaves, 3 to 10 cm in length. Greenish male flowers in long terminal buds, female flowers in leaf axils. Fruit in ovoid, angular and thorny achenes, 3 to 4 mm in length.

Shrub or small tree of up to 9 m, very ramified. Alternate leaves, ovate, from 8 to 20 cm, acuminate, cordate at the base, entire. Inflorescence in terminal panicles; flowers 4 to 5.3 cm in diameter; pink or white petals, obovate to broadly oval. Capsule (fruit) ovoid to globular-ovoid, 3 to 4 cm, usually with soft spines. Seeds with a red aril.

Annual erect plant, up to 2 m in height.  Leaf with three membranous leaflets, oval to ovate, 6 to 12 cm in length.  Flowers, 10 to 20 in number, pink, in peduncles.  Pod (fruit) linear, slightly curved, up to 30 cm in length, with three longitudinal ribs in each valve.  Ellipsoid seeds, approx. 2 cm in length, white with a brown mark.