Coriander is native to regions spanning from southern Europe and northern Africa to southwestern Asia. It is a soft plant growing to 50 cm (20 in) tall. The leaves are variable in shape, broadly lobed at the base of the plant, and slender and feathery higher on the flowering stems. The flowers are borne in small umbels, white or very pale pink, asymmetrical, with the petals pointing away from the center of the umbel longer (5–6 mm or 0.20–0.24 in) than those pointing toward it (only 1–3 mm or 0.039–0.118 in long). The fruit is a globular, dry schizocarp 3–5 mm (0.12–0.20 in) in diameter. The seeds are generally used as a spice or an added ingredient in other foods or recipes, although sometimes they are eaten alone.
First attested in English late fourteenth century, the word coriander derives from the Old French: coriandre, which comes from Latin: coriandrum, in turn from Ancient Greek: κορίαννον koriannon. The earliest attested form of the word is the Mycenaean Greek 𐀒𐀪𐀊𐀅𐀙 ko-ri-ja-da-na (written in Linear B syllabic script, reconstructed as koriadnon), similar to the name of Minos's daughter Ariadne, which later evolved to koriannon or koriandron.
Coriander grows wild over a wide area of Western Asia and southern Europe, prompting the comment, "It is hard to define exactly where this plant is wild and where it only recently established itself." Fifteen desiccated mericarps were found in the Pre-Pottery Neolithic B level of the Nahal Hemar Cave in Israel, which may be the oldest archaeological find of coriander. About half a litre of coriander mericarps were recovered from the tomb of Tutankhamen, and because this plant does not grow wild in Egypt, Zohary and Hopf interpret this find as proof that coriander was cultivated by the ancient Egyptians.
Coriander seems to have been cultivated in Greece since at least the second millennium BC. One of the Linear B tablets recovered from Pylos refers to the species as being cultivated for the manufacture of perfumes, and it appears that it was used in two forms: as a spice for its seeds and as a herb for the flavour of its leaves. This appears to be confirmed by archaeological evidence from the same period: the large quantities of the species retrieved from an Early Bronze Age layer at Sitagroi in Macedonia could point to cultivation of the species at that time.
Coriander was brought to the British colonies in North America in 1670, and was one of the first spices cultivated by early settlers.
All parts of the plant are edible, but the fresh leaves and the dried seeds are the parts most traditionally used in cooking. Coriander is common in South Asian, Southeast Asian, Indian, Middle Eastern, Caucasian, Central Asian, Mediterranean, Tex-Mex, Latin American, Brazilian, Portuguese, Chinese and African cuisines.
The leaves are variously referred to as coriander leaves, fresh coriander, dhania, Chinese parsley, or (in North America) cilantro.
It should not be confused with culantro (Eryngium foetidum L.), an apiaceae like coriander (Coriandrum sativum L.) but in a different genus. Culantro has a distinctly different spiny appearance, a more potent volatile leaf oil and a stronger aroma.
The fresh leaves are an ingredient in many Indian foods (such as chutneys and salads); in Chinese and Thai dishes; in Mexican cooking, particularly in salsa and guacamole and as a garnish; and in salads in Russia and other CIS countries. Chopped coriander leaves are a garnish on Indian dishes such as dal. As heat diminishes their flavour, coriander leaves are often used raw or added to the dish immediately before serving. In Indian and Central Asian recipes, coriander leaves are used in large amounts and cooked until the flavour diminishes. The leaves spoil quickly when removed from the plant, and lose their aroma when dried or frozen.
The word coriander in food preparation may refer solely to these seeds (as a spice), rather than to the plant. The seeds have a lemony citrus flavour when crushed, due to terpenes linalool and pinene. It is described as warm, nutty, spicy, and orange-flavoured.
The variety C. s. vulgare has a fruit diameter of 3–5 mm (0.12–0.20 in), while var. microcarpum fruits have a diameter of 1.5–3 mm (0.059–0.118 in). Large-fruited types are grown mainly by tropical and subtropical countries, e.g. Morocco, India and Australia, and contain a low volatile oil content (0.1-0.4%). They are used extensively for grinding and blending purposes in the spice trade. Types with smaller fruit are produced in temperate regions and usually have a volatile oil content of around 0.4-1.8%, so are highly valued as a raw material for the preparation of essential oil.
It is commonly found both as whole dried seeds and in ground form. Roasting or heating the seeds in a dry pan heightens the flavour, aroma and pungency. Ground coriander seed loses flavour quickly in storage and is best ground fresh. Coriander seed is a spice in garam masala and Indian curries which often employ the ground fruits in generous amounts together with cumin ,acting as a thickener in a mixture called dhana jeera .
Outside of Asia, coriander seed is used widely in the process for pickling vegetables. In Germany and South Africa (see boerewors), the seeds are used while making sausages. In Russia and Central Europe, coriander seed is an occasional ingredient in rye bread (e.g. borodinsky bread), as an alternative to caraway.
Coriander seeds are used in brewing certain styles of beer, particularly some Belgian wheat beers. The coriander seeds are used with orange peel to add a citrus character.
Flowering coriander for aphid control in lettuce
In the Salinas Valley of California, aphids have been one of the worst pest in the lettuce fields, and the USDA Cooperative Extension Service has been investigating organic methods for aphid control, and experimented with coriander plants and alyssum plants when intercropped with the lettuce and allowed to flower, attracts beneficial insects like Hoverflies. The Hoverflies lay their eggs and their larvae eat the aphids, up to 150 aphids per day before they mature into flying adults. 
The nutritional profile of coriander seeds is different from the fresh stems or leaves. Leaves are particularly rich in vitamin A, vitamin C and vitamin K, with moderate content of dietary minerals (table above). Although seeds generally have lower content of vitamins, they do provide significant amounts of dietary fiber, calcium, selenium, iron, magnesium and manganese.
Taste and smell
Different people may perceive the taste of coriander leaves differently. Those who enjoy it say it has a refreshing, lemony or lime-like flavor, while those who dislike it have a strong aversion to its taste and smell, characterizing it as soapy or rotten. Twin studies have shown that 80% of identical twins shared the same preference for the herb, but fraternal twins agreed only about half the time, strongly suggesting a genetic component to the preference. In a genetic survey of nearly 30,000 people, two genetic variants linked to perception of coriander have been found, the most common of which is a gene involved in sensing smells. The gene, OR6A2, lies within a cluster of olfactory-receptor genes, and encodes a receptor that is highly sensitive to aldehyde chemicals. Flavor chemists have found that the coriander aroma is created by a half-dozen or so substances, and most of these are aldehydes. Those who dislike the taste are sensitive to the offending unsaturated aldehydes, while simultaneously may also be unable to detect the aromatic chemicals that others find pleasant. Association between its taste and several other genes, including a bitter-taste receptor, have also been found.
Other herbs are used where they grow in much the same way as coriander leaves.
- Eryngium foetidum has a similar, but more intense, taste. It is known as culantro, and is found in Mexico, South America and the Caribbean.
- Persicaria odorata is commonly called Vietnamese coriander, or rau răm. The leaves have a similar odour and flavour to coriander. It is a member of the Polygonaceae, or buckwheat family.
- Papaloquelite is one common name for Porophyllum ruderale subsp. macrocephalum, a member of the Compositae or Asteraceae, the sunflower family. This species is found growing wild from Texas to Argentina.
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- Media related to Coriandrum sativum at Wikimedia Commons