''Xanthium'' (cocklebur) is a genus of flowering plants in the tribe

Heliantheae The Heliantheae (sometimes called the sunflower tribe) are the third-largest tribe in the sunflower family (Asteraceae). With some 190 genera and nearly 2500 recognized species, only the tribes Senecioneae and Astereae are larger. The name is de ...

within the family Asteraceae, native to the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

and eastern Asia and some parts of south Asia .

Description

Cockleburs are coarse,

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

annual plant An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical ...

s growing to tall. 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 ...

are spirally arranged, with deeply toothed margins. Some species, notably ''

Xanthium spinosum ''Xanthium spinosum'' (also known as ''Acanthoxanthium spinosum'') is a species of flowering plant in the aster family known by many common names, including spiny cocklebur, prickly burweed and Bathurst burr. This species is part of the genus '' ...

'', are also very thorny with long, slender spines at the leaf bases.Flora of North America Vol. 21 Page 19, Lampourde, ''Xanthium'' Linnaeus, Sp. Pl. 2: 987. 1753; Gen. Pl. ed. 5, 424. 1754.
/ref> The flower heads are of two types; One, in short terminal branches, produces only

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

. The other, in clusters in the axils of the leaves, produces seed. Unlike many other members of the family Asteraceae, whose seeds are airborne with a plume of silky hairs resembling miniature

parachute A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...

s, cocklebur seeds are produced in a hard, spiny,

globose A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ce ...

or oval double-chambered, single-seeded bur long. It is covered with stiff, hooked spines, which stick to fur and clothing and can be quite difficult to detach. These burs are carried long distances from the parent plant during seed dispersal by help of animals (

zoochorous In Spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, ...

Biology

Cockleburs are short-day plants, meaning they only initiate flowering when the days are getting shorter in the late summer and fall, typically from July to October in the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

. They can also flower in the tropics where the daylength is constant.

Diversity

Over 200 names have been proposed for species, subspecies, and varieties within the genus. Most of these are regarded as synonyms of highly variable species. Some recognize as few as two or three species in the genus. Th
Global Compositae Checklist
recognizes the following ;Accepted speciesFlann, C (ed) 2009+ Global Compositae Checklist
/ref> * '' Xanthium albinum'' (Widd.) Scholz & Sukopp – Mongolia * ''

Xanthium argenteum ''Xanthium'' (cocklebur) is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae, native to the Americas and eastern Asia and some parts of south Asia . Description Cockleburs are coarse, herbaceous annual plants ...

'' Widder – Chile * ''

Xanthium catharticum ''Xanthium'' (cocklebur) is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae, native to the Americas and eastern Asia and some parts of south Asia . Description Cockleburs are coarse, herbaceous annual plants ...

'' Kunth – Chile,

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

, Argentina * ''

Xanthium cavanillesii ''Xanthium orientale'' is a species of annual plant of the daisy family Asteraceae. Use by Native Americans The Zuni people use the plant for multiple purposes. The chewed seeds are rubbed onto the body before the cactus ceremony to protect it f ...

'' Shouw – Argentina * ''

Xanthium inaequilaterum ''Xanthium strumarium'' (rough cocklebur, clotbur, common cocklebur, large cocklebur, woolgarie bur) is a species of annual plants of the family Asteraceae. Some sources claim it originates in southern Europe and Asia, but has been extensively na ...

DC. Augustin Pyramus (or Pyrame) de Candolle (, , ; 4 February 17789 September 1841) was a Swiss botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple of years de Candolle ...

–

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, India, Southeast Asia * ''

Xanthium mongolicum ''Xanthium strumarium'' (rough cocklebur, clotbur, common cocklebur, large cocklebur, woolgarie bur) is a species of annual plants of the family Asteraceae. Some sources claim it originates in southern Europe and Asia, but has been extensively na ...

'' Kitag. – Mongolia * '' Xanthium orientale'' L. – Europe, North Africa, Middle East * ''

Xanthium pungens ''Xanthium strumarium'' (rough cocklebur, clotbur, common cocklebur, large cocklebur, woolgarie bur) is a species of annual plants of the family Asteraceae. Some sources claim it originates in southern Europe and Asia, but has been extensively na ...

'' Wallr. –

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

; naturalized in Eurasia * ''

Xanthium saccharosum ''Xanthium'' (cocklebur) is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae, native to the Americas and eastern Asia and some parts of south Asia . Description Cockleburs are coarse, herbaceous annual plants gr ...

'' * ''

'' L. – spiny cocklebur, burreed, Bathurst burr – very widespread, nearly

cosmopolitan Cosmopolitan may refer to: Food and drink * Cosmopolitan (cocktail), also known as a "Cosmo" History * Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953 Hotels and resorts * Cosmopoli ...

* '' Xanthium strumarium'' L. – clotbur, rough cocklebur, large cocklebur, common cocklebur – very widespread, nearly

;formerly included see ''

Ambrosia In the ancient Greek myths, ''ambrosia'' (, grc, ἀμβροσία 'immortality'), the food or drink of the Greek gods, is often depicted as conferring longevity or immortality upon whoever consumed it. It was brought to the gods in Olympus ...

'' * ''Xanthium artemisioides –

Ambrosia arborescens ''Ambrosia arborescens'' is a species of plant in the family Asteraceae. It is native to the Andes from Colombia south to Bolivia. In its native range, ''A. arborescens'' is used as a Medicinal plants, medicinal plant with analgesic, Anti-inflam ...

'' * ''Xanthium fruticosum –

Legal status

The cocklebur is legally listed as a noxious weed in the states of Arkansas and Iowa in the United States of America.

Toxicity and uses

The common cocklebur ('' Xanthium strumarium'') is a native of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It has become an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

worldwide. It invades agricultural lands and can be poisonous to livestock, including horses, cattle, and sheep. Some domestic animals will avoid consuming the plant if other forage is present, but less discriminating animals, such as pigs, will consume the plants and then sicken and die. The seedlings and seeds are the most toxic parts of the plants. Symptoms usually occur within a few hours, producing unsteadiness and weakness, depression, nausea and vomiting, twisting of the neck muscles, rapid and weak pulse, difficulty breathing, and eventually death. The plant also has been used for making yellow dye, hence the name of the genus (Greek ''xanthos'' = 'yellow'). The many species of this plant, which can be found in many areas, may actually be varieties of two or three species. The seed oil is edible. ''Xanthium strumarium'' is known as ''cang er zi'' (苍耳子) in traditional Chinese medicine. ''Xanthium'' is also used to treat nasal and sinus congestion. The spines and seeds of this fruit are rich in a chemical called carboxyatractyloside (CAT), formerly referred to as xanthostrumarin, which is the chemical that is responsible for most of the adverse effects from the use of ''cang er zi''. CAT has been shown to be a growth inhibitor in ''Xanthium'' and other plants, serving two functions, delaying seed germination and inhibiting the growth of other plants. Most of the chemical is concentrated in the spines. When the bur is prepared as an herbal remedy, the spines are usually removed, reducing the CAT content of the finished product.Cutler, H. G. and R. J. Cole. (1983). Carboxyatractyloside: A compound from ''Xanthium strumarium'' and ''Atractylis gummifera'' with plant growth inhibiting properties. ''Journal of Natural Products'' 46(5) 609-13.

In literature

In the

O. Henry William Sydney Porter (September 11, 1862 – June 5, 1910), better known by his pen name O. Henry, was an American writer known primarily for his short stories, though he also wrote poetry and non-fiction. His works include "The Gift of the M ...

novel '' Cabbages and Kings'' cockleburrs (spelt thus) are used as a plot device in the chapters ''Shoes'' and ''Ships'' to persuade the normally barefooted inhabitants of a town in the fictitious banana republic of Anchuria to buy shoes.

Gallery

File:Cocklebur Seedling West Texas 2003.jpg, ''X. strumarium'' File:Xanthium italicum ENBLA02.JPG, ''X. italicum'' File:Szerbtövis.jpg, ''X. spinosum'' File:XanthiumAlbinum2.jpg, ''X. albinum'' File:Arctium minus 2.jpg, Unidentified ''Xanthium''