Formerly called:
Labiatae

Lamiaceae, the mint family of flowering plants, with 236 genera and more than 7,000 species, the largest family of the order Lamiales. Lamiaceae is distributed nearly worldwide, and many species are cultivated for their fragrant leaves and attractive flowers. The family is particularly important to humans for herb plants useful for flavour, fragrance, or medicinal properties.

Physical description

Most members of the family are perennial or annual herbs with square stems, though some species are woody shrubs or subshrubs. The leaves are typically simple and oppositely arranged; most are fragrant and contain volatile oils. The flowers are usually arranged in clusters and feature two-lipped, open-mouthed, tubular corollas (united petals) with five-lobed bell-like calyxes (united sepals). The fruit is commonly a dry nutlet.

Major genera and species

Best known for its sharp fragrance is rosemary (Salvia rosmarinus), a Mediterranean species. Also Mediterranean is lavender (Lavandula officinalis), with fragrant blue to lavender flowers in leafless spikes. Hyssop (Hyssopus officinalis) was once used as a curative herb.

Venus's-flytrap. Venus's-flytrap (Dionaea muscipula) one of the best known of the meat-eating plants. Carnivorous plant, Venus flytrap, Venus fly trap
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There are about 350 species in the genus Thymus, all of which are Eurasian. Wild thyme (T. praecox), with scented leaves, is a creeping plant that is native in Europe but naturalized in eastern North America. Its foliage and flower heads resemble those of garden thyme (T. vulgaris), the source of the kitchen herb.

Of the 150 tropical species of Ocimum, basil (O. basilicum) is perhaps the most well known; the plant is likely native to India but is cultivated as a culinary herb in other regions. The genus Origanum, native in Europe, includes 15 to 20 species, chief among them being marjoram (O. majorana) and oregano (O. vulgare).

Catnip, or catmint (Nepeta cataria), a Eurasian perennial, grows to about 1 metre (3.3 feet) and has downy heart-shaped leaves with an aroma that is stimulating to cats.

Betony (Stachys officinalis) was once regarded as a cure-all, and other plants of the genus Stachys, or the woundworts generally, had supposed value as folk remedies. Self-heal, or heal-all (Prunella vulgaris), provided another important source of herbal medicine. The 40 to 50 species of the genus Lamium are known as dead nettles; they are low weedy plants that are sometimes cultivated as medicinal plants.

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Among the approximately 100 species of the genus Phlomis is Jerusalem sage (P. tuberosa), which rises to almost 2 metres (6.5 feet) and has clusters of purple flowers. It is native to Eurasia and is naturalized in North America. One of the 40 species of the African genus Leonotis, klip dagga, or lion’s ear (L. nepetifolia), is naturalized throughout the tropics; it has red-orange globe clusters of profuse flowers at the top of the 1- to 2-metre plants. See also Coleus; Mentha; Monarda.

The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Melissa Petruzzello.

peppermint

plant
Also known as: Mentha × piperita

peppermint, (Mentha ×piperita), strongly aromatic perennial herb of the mint family. Peppermint has a strong sweetish odor and a warm pungent taste with a cooling aftertaste. The leaves are typically used fresh as a culinary herb, and the flowers are dried and used to flavor candy, desserts, beverages, salads, and other foods. Its essential oil is also widely used as a flavoring.

Taxonomy

See also list of plants in the family Lamiaceae.

Physical description

Peppermint has square stems, stalked, dark green leaves with wavy or entire margins, and blunt oblong clusters of pinkish lavender flowers. The small flowers are not typical of other members of the family, having four rather than five united petals. As with other mints, the plant can spread aggressively by means of stolons (underground stems). The volatile oils are contained in resinous dots in the leaves and stems.

Types

The peppermint plant is a hybrid between watermint (Mentha aquatica) and spearmint (M. spicata) and is particularly cultivated in Europe, Asia, and North America. Natural hybridization among wild species has yielded many varieties of peppermint, but only two, the black and the white, are recognized by growers. Black peppermint, also called English peppermint or mitcham mint, is extensively grown in the United States and has purplish stems. The white variety is less hardy and less productive, but its oil is considered more delicate in odor and obtains a higher price.

Chef tossing vegetables in a frying pan over a burner (skillet, food).
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Essential oil

Oil of peppermint, a volatile essential oil distilled with steam from the herb, is widely used for flavoring confectionery, chewing gum, dentifrices, and medicines. Pure oil of peppermint is nearly colorless. It consists principally of menthol and menthone. Menthol, also called mint camphor or peppermint camphor, has long been used medicinally as a soothing balm.

The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Melissa Petruzzello.