dissected, with the ultimate segments filiform, about 0.5 mm wide. Its leaves are similar to those of dill, yet slightly thinner in comparison. 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.

Cultivation and uses
Fennel is widely cultivated, both in its native range and elsewhere, for its edible, strongly-flavoured leaves and seeds. The flavour is similar to that of anise and star anise, though usually not so strong.

The Florence Fennel (Foeniculum vulgare

Azoricum Group; syn. F. vulgare var. azoricum) is a Cultivar Group with inflated leaf bases which form a bulb-like structure. It is of cultivated origin, and has a mild anise-like flavour, but is more aromatic and sweeter. Its flavour comes from anethole, an aromatic compound also found in anise and star anise.

Florence fennel plants are smaller than the wild type and have inflated leaf bases which are eaten as a vegetable, both raw and cooked. There are several cultivars of Florence fennel, which is also known by several other names, notably the Italian name finocchio. In North American supermarkets, it is often mislabelled as "anise".Fennel has become naturalised along roadsides, in pastures, and in other open sites in many regions, including northern Europe, the United States, southern Canada and in much of Asia and Australia. It propagates well by seed, and is considered an invasive species and a weed in Australia and the United States (see Santa Cruz Island).

Florence fennel was one of the three main herbs used in the preparation of Absinthe, an alcoholic mixture which originated as a medicinal elixir in Switzerland and became, by the late 1800s, a popular drink believed by many to have psychoactive properties beyond those found in other alcoholic beverages. Due to these beliefs, Absinthe was banned in most countries by the 1940s, but a recent relaxation of laws governing its production, importation and sale has caused a moderate resurgence in consumption. Many modern preparations marketed under the name "Absinthe" do not make use of fennel as did the traditional recipes.

Culinary uses

Fennel is also used as a flavouring in some natural toothpastes. Some people employ it as a diuretic; while others have used it to improve the milk supply of breastfeeding mothers, it has shown neurotoxicity in certain cases where the mother ingested it as an herbal tea to enhance her breast milk.

Many cultures in the Indian subcontinent and the Middle East incorporate fennel seed into their culinary traditions. It is an essential ingredient in the Bengali/Oriya spice mixture panch phoron and in Chinese five-spice powders. It is known as saunf or mauti saunf in Hindi and Urdu, mouri in Bengali, and shombu or peruncheeragam in Tamil language. In the west, fennel seed is a very common ingredient in Italian sausages and northern European rye breads.

Many egg, fish, and other dishes employ fresh or dried fennel leaves. Florence fennel is a key ingredient in some Italian and German salads, often tossed with chicory and avocado, or it can be braised and served as a warm side dish. It may be blanched and/or marinated, or cooked in risotto. In all cases, the leaves lend their characteristically mild, anise-like flavour.

Medical uses
Fennel contains anethole, and this, or its polymers, act as phytoestrogens.This can explain some of fennel's action.

Essential oil of sweet Fennel is included in some pharmacopoeias. It is traditionally used in medicine to treat chills and stomach problems (carminative, antimicrobal action and so on). In fact, making a strong tea with Fennel seeds is very effective in relieving bloating and gas.

Fennel leaves can be boiled, the steam inhaled to relieve croup, asthma, and bronchitis.

Fennel contains Anethole, an antispasmatic, alongside other pharmacologically active substances.

Fennel essential oil is used in soaps, and some perfumes.

Etymology and history
Etymologically, the word fennel developed from Middle English fenel, fenyl; Anglo-Saxon fenol, finol, from Latin feniculum, foeniculum, diminutive of fenum, foenum, "hay". The actual Latin word for the plant was ferula, which is now used as the genus name of a related plant.

In Ancient Greek, fennel was called marathon (μάραθον), and is attested in Linear B tablets as ma-ra-tu-wo. John Chadwick notes that this word is the origin of the placename Marathon (meaning place of fennel), site of the Battle of Marathon in 490 BC; however, Chadwick wryly notes that he has "not seen any fennel growing there now".In Greek mythology, Prometheus used the stalk of a fennel plant to steal fire from the gods.

In medieval times fennel was used in conjunction with St John's wort to keep away witchcraft and other evil things. This practice may have originated from fennel's use as an insect repellent.

Fennel is thought to be one of the nine herbs held sacred by the Anglo-Saxons. The other eight are not entirely certain, but were probably mugwort (Artemisia vulgaris), greater plantain (Plantago major), watercress (Nasturtium officinale), wild chamomile (Matricaria recutita), stinging nettle (Urtica dioica), crab apple (Malus sylvestris), chervil (Anthriscus cerefolium), and viper's bugloss (Echium vulgare).