''Lactuca'', commonly known as

lettuce Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...

, is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of flowering plants in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae ...

. The genus includes at least 50 species, distributed worldwide, but mainly in temperate

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...

. Its best-known representative is the garden lettuce (''Lactuca sativa''), with its many varieties. "Wild lettuce" commonly refers to the wild-growing relatives of common garden lettuce. Many species are common

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

s. ''Lactuca'' species are diverse and take a wide variety of forms. They are annuals, biennials, perennials, or

shrubs A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

. Their

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

have yellow, blue, or white ray florets. Some species are bitter-tasting. Most wild lettuces are

xerophyte A xerophyte (from Ancient Greek language, Greek ξηρός ''xeros'' 'dry' + φυτόν ''phuton'' 'plant') is a species of plant that has adaptations to survive in an environment with little liquid water, such as a desert such as the Sahara or pl ...

s, adapted to dry habitat types. Some occur in more moist areas, such as the mountains of central

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Diversity

There are different concepts of the species within ''Lactuca''. It is not clear how many distinct species are known, and estimates vary from 50''Lactuca''.
Flora of China. to 75''Lactuca''.
Flora of North America. so far. Species include:GRIN Species Records of ''Lactuca''.
Germplasm Resources Information Network (GRIN).''Lactuca''.
The Plant List. Royal Botanic Gardens, Kew, and Missouri Botanical Garden. *''

Lactuca acanthifolia ''Lactuca'', commonly known as lettuce, is a genus of flowering plants in the family Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Its best-known representative is the garden lettuce ...

'' (

Crete Crete ( el, Κρήτη, translit=, Modern: , Ancient: ) is the largest and most populous of the Greek islands, the 88th largest island in the world and the fifth largest island in the Mediterranean Sea, after Sicily, Sardinia, Cyprus, ...

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula ...

) *'' Lactuca aculeata'' (

Asia Minor Anatolia, tr, Anadolu Yarımadası), and the Anatolian plateau, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The re ...

) *''

Lactuca acuminata ''Lactuca floridana'', commonly known as woodland lettuce, Florida lettuce, or false lettuce is a North American species of wild lettuce. It is native across much of central Canada and the eastern and central United States. ''Lactuca floridan ...

'' *''

Lactuca adenophora ''Lactuca'', commonly known as lettuce, is a genus of flowering plants in the family Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Its best-known representative is the garden lettuce ...

'' *''

Lactuca alpestris ''Lactuca alpestris'' is a species of plant native to Crete in the Ida mountains and is a relative of lettuce. It is perennial and has yellow flowers. Its achenes are 7m to 8m long. The species grows on rocky slopes, dwarf shrub communities, ca ...

'' (Crete) *''Lactuca alpina'' (syn. ''

Cicerbita alpina ''Cicerbita alpina'', commonly known as the alpine sow-thistle or alpine blue-sow-thistle is a perennial herbaceous species of plant sometimes placed in the genus ''Cicerbita'' of the family Asteraceae, and sometimes placed in the genus ''Lactuca ...

'') (

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

) - alpine sow-thistle, alpine blue-sow-thistle, tall blue lettuce *''

Lactuca altaica ''Lactuca serriola'', also called prickly lettuce, milk thistle (not to be confused with '' Silybum marianum'', also called milk thistle), compass plant, and scarole, is an annual or biennial plant in the tribe Cichorieae within the family Aster ...

'' (Eurasia) *''

Lactuca attenuata ''Lactuca'', commonly known as lettuce, is a genus of flowering plants in the family Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Its best-known representative is the garden lettuce ...

''''Lactuca attenuata''.
''Flora Zambesiaca''. Royal Botanic Gardens, Kew. (Africa) *''

Lactuca aurea ''Lactuca'', commonly known as lettuce, is a genus of flowering plants in the family Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Its best-known representative is the garden lettuce ...

'' (Europe) *''

Lactuca azerbaijanica ''Lactuca'', commonly known as lettuce, is a genus of flowering plants in the family Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Its best-known representative is the garden lettuce ...

'' (

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

) *''

Lactuca biennis ''Lactuca biennis'' is a North American species of wild lettuce known by the common names tall blue lettuce and blue wood lettuce. It is widespread across much of the United States and Canada from Alaska and Yukon south as far as California, Ne ...

'' (North America) – tall blue lettuce, blue wood lettuce *'' Lactuca calophylla'' (Africa) *''

Lactuca canadensis ''Lactuca canadensis'' is a species of wild lettuce known by the common names Canada lettuce, Canada wild lettuce, tall lettuce, and Florida blue lettuce.Weakley, Alan S''. Flora of the Southern and Mid-Atlantic States.'' UNC Herbarium, North Ca ...

'' (North America) – Canada wild lettuce, tall lettuce *'' Lactuca corymbosa'' ( Congo) *'' Lactuca crambifolia'' (

Turkestan Turkestan, also spelled Turkistan ( fa, ترکستان, Torkestân, lit=Land of the Turks), is a historical region in Central Asia corresponding to the regions of Transoxiana and Xinjiang. Overview Known as Turan to the Persians, western Turk ...

) *'' Lactuca cyprica'' (

Cyprus Cyprus ; tr, Kıbrıs (), officially the Republic of Cyprus,, , lit: Republic of Cyprus is an island country located south of the Anatolian Peninsula in the eastern Mediterranean Sea. Its continental position is disputed; while it is ...

) - Cyprus lettuce *'' Lactuca deltoidea'' *'' Lactuca dissecta'' (Asia) *'' Lactuca dolichophylla'' (Asia) *'' Lactuca dregeana'' (

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

) – ''melkdissel'', ''slaaidissel'' *'' Lactuca dumicola'' *'' Lactuca erostrata''Bano, R. and M. Qaiser. (2011)
A taxonomic revision of the genus ''Lactuca'' L. (Cichorieae-Asteraceae) from Pakistan and Kashmir.
''Pakistan Journal of Botany'' 43(5) 2259–268. (

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

) *'' Lactuca fenzlii'' *'' Lactuca floridana'' (North America) – Florida lettuce, woodland lettuce *'' Lactuca georgica'' (Asia) *'' Lactuca glaucifolia'' (Asia) *'' Lactuca graciliflora'' (Asia) *'' Lactuca graminifolia'' (Americas) – grassleaf lettuce *'' Lactuca haimanniana'' *'' Lactuca henryi'' *'' Lactuca hirsuta'' (North America) – downy lettuce, hairy lettuce *'' Lactuca hispida'' *'' Lactuca homblei''''Lactuca homblei''.
''Flora Zambesiaca''. Royal Botanic Gardens, Kew. (

Zaire Zaire (, ), officially the Republic of Zaire (french: République du Zaïre, link=no, ), was a Congolese state from 1971 to 1997 in Central Africa that was previously and is now again known as the Democratic Republic of the Congo. Zaire was, ...

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are t ...

) *'' Lactuca imbricata''''Lactuca imbricata''.
''Flora Zambesiaca''. Royal Botanic Gardens, Kew. (Africa) *'' Lactuca indica'' (Asia) - Indian lettuce *'' Lactuca inermis'' (Africa,

Arabian Peninsula The Arabian Peninsula, (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") or Arabia, is a peninsula of Western Asia, situated northeast of Africa on the Arabian Plat ...

) *'' Lactuca intricata'' (Albania, Greece, Turkey) *'' Lactuca jamaicensis'' (

Jamaica Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of Hispa ...

) *'' Lactuca kanitziana'' *'' Lactuca kochiana'' *'' Lactuca lasiorhiza''''Lactuca lasiorhiza''.
''Flora Zambesiaca''. Royal Botanic Gardens, Kew. (Africa) *'' Lactuca ludoviciana'' (North America) – biannual lettuce *'' Lactuca macrophylla'' *'' Lactuca mira'' *'' Lactuca muralis'' *'' Lactuca mwinilungensis''''Lactuca mwinilungensis''.
''Flora Zambesiaca''. Royal Botanic Gardens, Kew. (Zaire, Zambia) *'' Lactuca nana''''Lactuca nana''.
''Flora Zambesiaca''. Royal Botanic Gardens, Kew. (Africa) *'' Lactuca orientalis'' (Asia,

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a List of transcontinental countries, transcontinental country spanning the North Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via a land bridg ...

) *'' Lactuca palmensis'' (

Canary Islands The Canary Islands (; es, :es:Canarias, Canarias, ), also known informally as the Canaries, are a Spanish Autonomous communities of Spain, autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to ...

) *'' Lactuca paradoxa'' *'' Lactuca parishii'' *'' Lactuca perennis'' (Europe) – blue lettuce, mountain lettuce *'' Lactuca persica'' *'' Lactuca petrensis'' *''

Lactuca quercina ''Lactuca quercina'' is a species of wild lettuce native to Europe and Asia. It is an annual or biennial herb in the tribe Cichorieae within the family Asteraceae growing from a taproot to maximum heights of or more. ''Lactuca quercina'' conta ...

'' (Eurasia) *'' Lactuca racemosa'' *'' Lactuca raddeana'' (Asia) *'' Lactuca rechingeriana'' *'' Lactuca rosularis'' (Iran, Turkmenistan) *'' Lactuca saligna'' (Eurasia) – willow lettuce, least lettuce, narrow-leaf lettuce *'' Lactuca sativa'' – lettuce, garden lettuce *'' Lactuca scarioloides'' (western Asia) *'' Lactuca schulzeana'' (

Angola , national_anthem = "Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordinat ...

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the ...

, Zaire) *'' Lactuca schweinfurthii'' (Africa) *''

Lactuca serriola ''Lactuca serriola'', also called prickly lettuce, milk thistle (not to be confused with '' Silybum marianum'', also called milk thistle), compass plant, and scarole, is an annual or biennial plant in the tribe Cichorieae within the family Aster ...

'' (Africa, Asia, Europe) – prickly lettuce, compassplant, scarole, milk thistle *'' Lactuca setosa'' (Africa) *'' Lactuca sibirica'' (Eurasia) *'' Lactuca singularis'' (Spain) *'' Lactuca songeensis'' *'' Lactuca spinidens'' (Tajikistan, Turkmenistan) *'' Lactuca stebbinsii''Kilian, N. (2001)
''Lactuca stebbinsii'' (Lactuceae, Compositae), a puzzling new species from Angola.
''Willdenowia - Annals of the Botanic Garden and Botanical Museum Berlin - Dahlem'' 31(1) 71–8. (Angola) *'' Lactuca takhtadzhianii'' (Armenia) *''

Lactuca tatarica ''Lactuca tatarica'', known as blue lettuce, is a Eurasian flowering plant in the tribe Cichorieae within the family Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in ov ...

'' (Northern Hemisphere) – blue lettuce *'' Lactuca tenerrima'' (southern Europe, Morocco) *'' Lactuca tetrantha'' (Cyprus) *'' Lactuca tinctociliata'' *'' Lactuca triangulata'' (Asia) *'' Lactuca triquetra'' *'' Lactuca tuberosa'' (Eurasia) *'' Lactuca ugandensis'' *'' Lactuca undulata'' (Asia) *'' Lactuca viminea'' (Africa, Asia, Europe) – pliant lettuce *'' Lactuca virosa'' (Europe, northern Africa) – bitter lettuce, great lettuce *'' Lactuca watsoniana'' (

Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

) *'' Lactuca winkleri'' (Tajikistan)

Ecology

''Lactuca'' species are used as food plants by the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e of many Lepidoptera species.

Etymology

'Lactuca' is derived from

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

and means 'having milky sap'. 'Lactuca' and 'lactic' (of or relating to milk) have the same root word, 'lactis'.Gledhill, David (2008). "The Names of Plants". Cambridge University Press. (hardback), (paperback). pp 228

References

External links

Jepson Manual Treatment
{{Taxonbar, from=Q578052 Asteraceae genera