Asterales is an order of dicotyledonous flowering plants that includes the large family Asteraceae known for composite flowers made of florets, and ten families related to the Asteraceae. While asterids in general are characterized by fused petals, composite flowers consisting of many florets create the false appearance of separate petals.
Lettuce 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, such as soups, sandwiches and wraps; it can also be grilled. One variety, celtuce, is grown for its stems, which are eaten either raw or cooked. In addition to its main use as a leafy green, it has also gathered religious and medicinal significance over centuries of human consumption. Europe and North America originally dominated the market for lettuce, but by the late 20th century the consumption of lettuce had spread throughout the world. As of 2021, world production of lettuce and chicory was 27 million tonnes, 53 percent of which came from China.
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.
Lactucarium is the milky fluid secreted by several species of lettuce, especially Lactuca virosa, usually from the base of the stems. It is known as lettuce opium because of its sedative and analgesic properties. It has also been reported to promote a mild sensation of euphoria. Because it is a latex, lactucarium physically resembles opium, in that it is excreted as a white fluid and can be reduced to a thick smokable solid.
The sea lettuces comprise the genus Ulva, a group of edible green algae that is widely distributed along the coasts of the world's oceans. The type species within the genus Ulva is Ulva lactuca, lactuca being Latin for "lettuce". The genus also includes the species previously classified under the genus Enteromorpha, the former members of which are known under the common name green nori.
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, and is often called wild lettuce, bitter lettuce, laitue vireuse, opium lettuce, poisonous lettuce, tall lettuce, great lettuce or rakutu-karyumu-so.
Lactuca serriola, also called prickly lettuce, milk thistle, compass plant, and scarole, is an annual or biennial plant in the tribe Cichorieae within the family Asteraceae. It has a slightly fetid odor and is commonly considered a weed of orchards, roadsides and field crops. It is the closest wild relative of cultivated lettuce.
Prenanthes is a genus of plant in the family Asteraceae, often referred to as rattlesnake root.
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 as Lactuca alpina. It is native to upland and mountainous parts of Europe.
Picconia azorica, locally known as pau-branco, is a species of Picconia common to the majority of islands of the Portuguese archipelago of the Azores, where it is endemic. It can grow to a medium-sized tree, though it is usually found in the form of a shrub. It is threatened by habitat loss.
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 North America. It naturalized in the western part of the continent as well as in Eurasia.
Nabalus is a genus of Asian and North American flowering plants in the tribe Cichorieae within the family Asteraceae.
Lactuca perennis, common names: mountain lettuce, blue lettuce or perennial lettuce, is a perennial herbaceous plant species belonging to the genus Lactuca of the family Asteraceae. It is widespread across most of central and southern Europe. Its leaves are edible.
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.
Hypericum foliosum, the shining St John's wort, is a species of flowering plant in the family Hypericaceae. It is a bushy shrub endemic to the Portuguese Azores Islands with golden yellow petals and many stems. The species was described by William Aiton in 1789 and was later placed into section Androsaemum of the genus Hypericum by Norman Robson in 1984. It has a diverse essential oil profile made up mostly of monoterpene hydrocarbons, and significant concentrations of various medicinally useful phenols and carotenoids. Populations of the plant are small in number, but quick to colonize cleared areas like groves, landslide areas, and volcanic ash deposits. It is parasitized by fungus and by moth species, but is not considered endangered by the IUCN. H. foliosum is used in traditional medicine on the Azores for diuretic, hepatoprotective, and antihypertensive purposes. It also has in vitro antibiotic and antioxidizing capabilities.
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 50–200 cm (19.5–78.5 in) or more.
Lactuca tenerrima is a species of wild lettuce native to southern France, Spain, the Balearic Islands, and the Atlas Mountains of Morocco. Unlike other species in its genus Lactuca, even in its family Asteraceae, it does not produce bitter-tasting sesquiterpene lactones.
Lactuca aculeata is a species of wild lettuce native to Anatolia, the Levant, Iraq and Iran. A very prickly plant, it is closely related to Lactuca serriola and Lactuca sativa, and can readily interbreed with them. It is possible that Lactuca aculeata contributed to the gene pool of cultivated lettuce.
Lactuca palmensis is a species of wild lettuce endemic to the Canary Islands. DNA evidence shows that it is closely related to the African and European species of Lactuca, while the Azores endemic Lactuca watsoniana is more closely related to the North American lineage.
Lactuca dolichophylla, the long-leaved lettuce, is a species of wild lettuce found in Afghanistan, Pakistan, West Himalaya, Nepal, Xizang (Tibet), East Himalaya, south-central China, and Myanmar. It prefers to grow in thickets at c.3200 m above sea level. Its chromosome count is 2n=16.
