''Lactuca'', commonly known as

lettuce Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae mostly grown as a leaf vegetable. The leaves are most often used raw in Green salad, green salads, although lettuce is also seen in other kinds of food, such as sandwiche ...

, is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of flowering plants in the family

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

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

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

. 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, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

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

shrubs A shrub or 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 by their multiple ...

. Their

flower heads A pseudanthium (; : pseudanthia) 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, composite flowers ...

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

xerophyte A xerophyte () is a species of plant that has adaptations to survive in an environment with little liquid water. Examples of xerophytes include cacti, pineapple and some gymnosperm plants. The morphology and physiology of xerophytes are adapted to ...

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. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

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 ( ; , Modern Greek, Modern: , Ancient Greek, Ancient: ) is the largest and most populous of the Greek islands, the List of islands by area, 88th largest island in the world and the List of islands in the Mediterranean#By area, fifth la ...

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

) *'' Lactuca aculeata'' (

Asia Minor Anatolia (), also known as Asia Minor, is a peninsula in West Asia that makes up the majority of the land area of Turkey. It is the westernmost protrusion of Asia and is geographically bounded by the Mediterranean Sea to the south, the Aegean ...

) *''

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 florida ...

'' *''

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 continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

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

Lactuca altaica ''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 lettuc ...

'' (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 (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

) *''

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, New ...

'' (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, and tall lettuce. Its true native range is not clear, but it is considered to be a native of the eastern and central parts of Nort ...

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

Turkestan Turkestan,; ; ; ; also spelled Turkistan, is a historical region in Central Asia corresponding to the regions of Transoxiana and East Turkestan (Xinjiang). The region is located in the northwest of modern day China and to the northwest of its ...

) *'' Lactuca cyprica'' (

Cyprus Cyprus (), officially the Republic of Cyprus, is an island country in the eastern Mediterranean Sea. Situated in West Asia, its cultural identity and geopolitical orientation are overwhelmingly Southeast European. Cyprus is the List of isl ...

) - 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 Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

) – ''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, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...

) *'' Lactuca fenzlii'' *'' Lactuca floridana'' (North America) – Florida lettuce, woodland lettuce *'' Lactuca georgica'' (Asia) *'' Lactuca glaucifolia'' (Asia) *'' Lactuca graciliflora'' (Asia) *''

Lactuca graminifolia ''Lactuca graminifolia'', the grassleaf lettuce is a North American species of Lactuca, wild lettuce. It grows in Mexico, Central America, Hispaniola, and the southern United States from Arizona to Florida, Virginia and the Carolinas. Descriptio ...

'' (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, was the name of the Democratic Republic of the Congo from 1971 to 18 May 1997. Located in Central Africa, it was, by area, the third-largest country in Africa after Sudan and Algeria, and the 11th-la ...

Zambia Zambia, officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa. It is typically referred to being in South-Central Africa or Southern Africa. It is bor ...

) *''

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

Arabian Peninsula The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world. Geographically, the ...

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

Jamaica Jamaica is an island country in the Caribbean Sea and the West Indies. At , it is the third-largest island—after Cuba and Hispaniola—of the Greater Antilles and the Caribbean. Jamaica lies about south of Cuba, west of Hispaniola (the is ...

) *'' 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 muralis'', the wall lettuce, is a perennial flowering plant in the tribe Cichorieae within the family Asteraceae. It is also referred to as ''Mycelis muralis''.Parnell, J. and Curtis, T. 2012. ''Webb's An Irish Flora''. Cork University ...

'' *'' 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 ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

) *'' Lactuca palmensis'' (

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

) *'' 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'' co ...

'' (Eurasia) *'' Lactuca racemosa'' *'' Lactuca raddeana'' (Asia) *'' Lactuca rechingeriana'' *'' Lactuca rosularis'' (Iran, Turkmenistan) *''

Lactuca saligna ''Lactuca saligna'' is a species of wild lettuce known by the common name willowleaf lettuce, and least lettuce. It is native to Eurasia but it grows in many other places as an introduced species, including much of North America. It can be foun ...

'' (Eurasia) – willow lettuce, least lettuce, narrow-leaf lettuce *''

Lactuca sativa Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae mostly grown as a leaf vegetable. The leaves are most often used raw in green salads, although lettuce is also seen in other kinds of food, such as sandwiches, wraps an ...

'' – lettuce, garden lettuce *'' Lactuca scarioloides'' (western Asia) *'' Lactuca schulzeana'' (

Angola Angola, officially the Republic of Angola, is a country on the west-Central Africa, central coast of Southern Africa. It is the second-largest Portuguese-speaking world, Portuguese-speaking (Lusophone) country in both total area and List of c ...

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

, 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 Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species ...

'' (Northern Hemisphere) – blue lettuce *'' Lactuca tenerrima'' (southern Europe, Morocco) *'' Lactuca tetrantha'' (Cyprus) *'' Lactuca tinctociliata'' *'' Lactuca triangulata'' (Asia) *'' Lactuca triquetra'' *''

Lactuca tuberosa ''Lactuca tuberosa'' is an ornamental plant in the family Asteraceae. References Further reading * External links * Genetic information of ''Steptorhamphus tuberosus''
Lactuca, tuberosa {{Cichorieae-stub ...

'' (Eurasia) *'' Lactuca ugandensis'' *'' Lactuca undulata'' (Asia) *'' Lactuca viminea'' (Africa, Asia, Europe) – pliant lettuce *''

Lactuca virosa ''Lactuca virosa'' is a plant in the ''Lactuca'' (lettuce) genus, often ingested for its mild analgesic and sedative effects. It is related to common lettuce (''Lactuca sativa, L. sativa''), and is often called wild lettuce, bitter lettuce, lait ...

'' (Europe, northern Africa) – bitter lettuce, great lettuce *'' Lactuca watsoniana'' (

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

) *''

Lactuca winkleri ''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 lettuce, garden ...

'' (Tajikistan)

Ecology

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

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

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 spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

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
{{Authority control Asteraceae genera