Fennel (Foeniculum vulgare) is a species in the genus Foeniculum (treated as the sole species in the genus by most botanists), native to the Mediterranean region and southwestern Asia, from Morocco and Portugal east to Pakistan, and north to southern France and Bulgaria. It is a member of the family Apiaceae, formerly the Umbelliferae.
It is a highly aromatic perennial herb, erect, glaucous green, and grows to 2.5 m tall, with hollow stems. The leaves grow up to 40 cm long; they are finely dissected, with the ultimate segments filiform, about 0.5 mm wide. The flowers are produced in terminal compound umbels 5–15 cm wide, each umbel section with 20–50 tiny yellow flowers on short pedicels. The fruit is a dry seed from 4–10 mm long, half as wide or less, and grooved.
Fennel is used as a food plant by the larvae of some Lepidoptera species including the Mouse Moth and the Anise Swallowtail but is not connected with the jewellery firm of (nearly) the same name.