''Xanthium'' (cocklebur) 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 ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the tribe Heliantheae within 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 ...

, native to the

Americas The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...

and eastern

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

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 ...

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. Globally, 6% of all plant species and 15% of herbaceous plants (excluding trees and shrubs) are ...

s growing to tall. The leaves are spirally arranged, with deeply toothed margins. Some species, notably '' Xanthium spinosum'', 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 most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

. The other, in clusters in the axils of the leaves, produces seed. Unlike many other members of the family

, whose seeds are airborne with a plume of silky hairs resembling miniature

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

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

by help of animals ( zoochorous).

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 by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

. 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. The Global Compositae Checklist recognizes the following. ;Accepted speciesFlann, C (ed) 2009+ "Global Compositae Checklist"
/ref> * '' Xanthium albinum'' (Widd.) Scholz & Sukopp –

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

* '' Xanthium argenteum'' Widder –

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

* '' Xanthium catharticum'' Kunth –

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

* '' Xanthium cavanillesii'' Shouw –

* '' Xanthium inaequilaterum'' DC. –

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

* '' Xanthium mongolicum'' Kitag. –

* '' Xanthium orientale'' L. –

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 ...

North Africa North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

* '' Xanthium pungens'' Wallr. –

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

; naturalized in

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 ...

* '' Xanthium saccharosum'' * '' Xanthium spinosum'' L. – spiny cocklebur, burreed, Bathurst burr – very widespread, nearly cosmopolitan * '' Xanthium strumarium'' L. – clotbur, rough cocklebur, large cocklebur, common cocklebur – very widespread, nearly cosmopolitan ;formerly included * see ''

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

'' * ''Xanthium artemisioides – Ambrosia arborescens'' * ''Xanthium fruticosum – Ambrosia arborescens''

Legal status

The cocklebur is legally listed as a noxious weed in the states of

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

and

Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...

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, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It has become an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

worldwide. It invades agricultural lands and can be poisonous to

livestock Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The t ...

, 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 Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. It can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat. Over 30 d ...

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'' means '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'' (蒼耳子) in

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medicine, alternative medical practice drawn from traditional medicine in China. A large share of its claims are pseudoscientific, with the majority of treatments having no robust evidence ...

. ''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.

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''

Description

Biology

Diversity

Legal status

Toxicity and uses

Gallery

See also

References

Further reading