''Lactuca serriola'', also called prickly lettuce,
milk thistle
[ (not to be confused with '']Silybum marianum
''Silybum marianum'' is a species of thistle. It has various common names including milk thistle, blessed milkthistle, Marian thistle, Mary thistle, Saint Mary's thistle, Mediterranean milk thistle, variegated thistle and Scotch thistle (thou ...
'', also called milk thistle), compass plant, and scarole,[ is an ]annual
Annual may refer to:
*Annual publication, periodical publications appearing regularly once per year
** Yearbook
** Literary annual
*Annual plant
*Annual report
*Annual giving
*Annual, Morocco, a settlement in northeastern Morocco
*Annuals (band), ...
or biennial plant in the tribe Cichorieae
The Cichorieae (also called Lactuceae) are a tribe in the plant family Asteraceae that includes 93 genera, more than 1,600 sexually reproductive species and more than 7,000 apomictic species. They are found primarily in temperate regions of the E ...
within 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 w ...
. It has a slightly fetid odor
An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is caused by one or more volatilized chemical compounds ...
and is commonly considered a 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. ...
of orchard
An orchard is an intentional plantation of trees or shrubs that is maintained for food production. Orchards comprise fruit- or nut-producing trees which are generally grown for commercial production. Orchards are also sometimes a feature of ...
s, roadsides and field crops. It is the closest wild relative of cultivated lettuce (''Lactuca sativa
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, ...
'' L.).
''Lactuca serriola'' is known as the compass plant because in the sun the upper leaves twist round to hold their margins upright.
''Lactuca serriola'' is native to 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 ...
, Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
, and north 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 ...
, and has become naturalized elsewhere.
Description
''Lactuca serriola'' has a spineless reddish stem, containing a milky latex, growing up to .
The leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
get progressively smaller as they reach its top. They are oblong or lanceolate, often pinnately lobed and (especially for the lower leaves), waxy grey green. Fine spines are present along the veins and leaf edges. The undersides have whitish veins. They emit latex
Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well.
In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...
when cut.
The flower heads are wide, pale yellow, often tinged purple, with 12–20 ray flowers
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 w ...
but no disc flowers. The bracts are also often tinged purple. It flowers from July until September in the northern hemisphere. The achenes
An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not op ...
are grey, tipped with bristles. The pappus is white with equal length hairs.
Similar to '' Mycelis muralis'' but showing more than 5 florets.
It can cause pulmonary emphysema
Emphysema, or pulmonary emphysema, is a lower respiratory tract disease, characterised by air-filled spaces ( pneumatoses) in the lungs, that can vary in size and may be very large. The spaces are caused by the breakdown of the walls of the alv ...
in cattle feeding exclusively on the plant.
Culinary and medicinal uses
''Lactuca serriola'' can be eaten as a salad
A salad is a dish consisting of mixed, mostly natural ingredients with at least one raw ingredient. They are typically served at room temperature or chilled, though some can be served warm. Condiments and salad dressings, which exist in a va ...
, although it has something of a bitter taste. Young leaves can be eaten raw or cooked. Older leaves can be steamed. While unsubstantial, its roots have been used as a coffee substitute
Coffee substitutes are non-coffee products, usually without caffeine, that are used to imitate coffee. Coffee substitutes can be used for medical, economic and religious reasons, or simply because coffee is not readily available. Roasted grain b ...
.
Its presence in some ancient deposits has been linked more to its soporific
Hypnotic (from Greek ''Hypnos'', sleep), or soporific drugs, commonly known as sleeping pills, are a class of (and umbrella term for) psychoactive drugs whose primary function is to induce sleep (or surgical anesthesiaWhen used in anesthesia ...
properties which might suggest ritual use. The Ancient Greeks
Ancient Greece ( el, Ἑλλάς, Hellás) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity ( AD 600), that comprised a loose collection of cult ...
also believed its pungent juice to be a remedy against eye ulcers and Pythagoreans
Pythagoreanism originated in the 6th century BC, based on and around the teachings and beliefs held by Pythagoras and his followers, the Pythagoreans. Pythagoras established the first Pythagorean community in the ancient Greek colony of Kroton, ...
called the lettuce ''eunuch'' because it caused urination and relaxed sexual desire. Following its accidental introduction to North America, the Navajo
The Navajo (; British English: Navaho; nv, Diné or ') are a Native American people of the Southwestern United States.
With more than 399,494 enrolled tribal members , the Navajo Nation is the largest federally recognized tribe in the United ...
began to use the plant as a ceremonial emetic
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenteri ...
. In the island of 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, and ...
in Greece
Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...
the leaves and the tender shoots of a variety called maroula (μαρούλα) or agriomaroulo (αγριομάρουλο) are eaten boiled. It is used by a growing number of Jews
Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...
and Samaritans
Samaritans (; ; he, שומרונים, translit=Šōmrōnīm, lit=; ar, السامريون, translit=as-Sāmiriyyūn) are an ethnoreligious group who originate from the ancient Israelites. They are native to the Levant and adhere to Samarit ...
as the Maror
''Maror'' ( he, מָרוֹר ''mārôr'') refers to the bitter herbs eaten at the Passover Seder_in_keeping_with_the_biblical_commandment__"with_bitter_herbs_they_shall_eat_it."_(Book_of_Exodus.html" "title="mitzvah.html" "title="isan in the H ...
(bitter herb) on Pesach
Passover, also called Pesach (; ), is a major Jewish holiday that celebrates the The Exodus, Biblical story of the Israelites escape from slavery in Egypt, which occurs on the 15th day of the Hebrew month of Nisan, the first month of Aviv, or ...
.
''Lactuca serriola'' contains lactucarium
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 ...
, which is the milky sap (white latex) that flows through the stem of the plant. It is used as a medicinal herb when dried after contact with air. Although the standard definition of lactucarium requires its production from ''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 ('' L. sativa''), and is often called wild lettuce, bitter lettuce, laitue vireuse, opi ...
'', it was recognized that smaller quantities of lactucarium could be produced in a similar way from ''Lactuca sativa
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, ...
'' and ''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 Car ...
'' var. ''elongata'', and even that lettuce-opium obtained from ''Lactuca serriola'' or ''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'' contai ...
'' was of superior quality.
History
The Egyptian god Min
Min or MIN may refer to:
Places
* Fujian, also called Mǐn, a province of China
** Min Kingdom (909–945), a state in Fujian
* Min County, a county of Dingxi, Gansu province, China
* Min River (Fujian)
* Min River (Sichuan)
* Mineola (Am ...
is associated with this species of lettuce. Also, archaeobotanical evidence in Greek archaeological contexts is scanty, although uncarbonised seeds have been retrieved from a 7th-century BC deposit in a sanctuary of Hera
In ancient Greek religion, Hera (; grc-gre, Ἥρα, Hḗrā; grc, Ἥρη, Hḗrē, label=none in Ionic and Homeric Greek) is the goddess of marriage, women and family, and the protector of women during childbirth. In Greek mythology, she ...
on Samos
Samos (, also ; el, Σάμος ) is a Greece, Greek island in the eastern Aegean Sea, south of Chios, north of Patmos and the Dodecanese, and off the coast of western Turkey, from which it is separated by the -wide Mycale Strait. It is also a se ...
. It is also described by Theophrastus
Theophrastus (; grc-gre, Θεόφραστος ; c. 371c. 287 BC), a Greek philosopher and the successor to Aristotle in the Peripatetic school. He was a native of Eresos in Lesbos.Gavin Hardy and Laurence Totelin, ''Ancient Botany'', Routledge ...
. In mythology, Aphrodite
Aphrodite ( ; grc-gre, Ἀφροδίτη, Aphrodítē; , , ) is an ancient Greek goddess associated with love, lust, beauty, pleasure, passion, and procreation. She was syncretized with the Roman goddess . Aphrodite's major symbols inclu ...
is said to have laid Adonis
In Greek mythology, Adonis, ; derived from the Canaanite word ''ʼadōn'', meaning "lord". R. S. P. Beekes, ''Etymological Dictionary of Greek'', Brill, 2009, p. 23. was the mortal lover of the goddess Aphrodite.
One day, Adonis was gored by ...
in a lettuce bed, leading to the vegetable's association with food for the dead.
Pathogen resistance
''Lactuca serriola'' is the wild progenitor of cultivated lettuce (''Lactuca sativa
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, ...
''), and can be affected by lettuce downy mildew, one of the most serious diseases of lettuce. ''L. serriola'' has shown resistance to the plant pathogen '' Bremia lactucae'', the cause of the disease. This pathogen is able to undergo sexual reproduction, and once virulent strains have been produced, can undergo rapid asexual reproductive cycles. As a result, there are many strains, which vary in virulence.
Resistance to ''Bremia lactucae'' in ''Lactuca serriola'' is due to ''Dm'' genes, or single dominant genes. Nine of the dominant genes that confer resistance are ''Dml, Dm, Dm3, Dm6, Dml4, Dml5, DmlO,'' ''Dm5/8, Dm10'', ''Dm4, Dm7, Dm11,'' and ''Dm13''. These genes are mapped in four linkage groups, so the genes within each group will be more likely to be inherited together. ''Lactuca serriola'' and ''B. lactucae'' have a gene-for-gene relationship
The gene-for-gene relationship was discovered by Harold Henry Flor who was working with rust (''Melampsora lini'') of flax ('' Linum usitatissimum''). Flor showed that the inheritance of both resistance in the host and parasite ability to cause d ...
, meaning that each resistance gene in the plant is associated with a specific gene in the pathogen, with avirulence being dominant to virulence. The possible combinations of these ''Dm'' genes can provide the plant with resistance to multiple strains of ''Bremia lactucae''.
Testing for the presence of new resistance factors is conducted by screening samples of ''L. serriola'' with various isolates of ''B. lactucae.'' Samples of ''L. serriola'' can be found around the world with genetic diversity between populations regarding the ''Dm'' genes. This genetic diversity is considered a resource for lettuce breeding because it provides a greater variety of genes to be used in response to new strains of ''B. lactucae'', which continually emerge. There is especially high diversity within the Mediterranean area and Southwest Asia, but ''L. serriola'' has established populations on all continents and has the most widespread distribution compared to other ''Lactuca'' species.
References
External links
Prickly Lettuce on Virginia Tech Weed Identification Guide
Jepson Manual Treatment
*
photo of herbarium specimen at Missouri Botanical Garden, collected in North Dakota in 2014
{{Taxonbar, from=Q533481
serriola
Medicinal plants
Flora of Europe
Flora of Asia
Flora of North Africa
Leaf vegetables
Plants described in 1756
Taxa named by Carl Linnaeus