''Bidens pilosa'' is an annual species of herbaceous flowering plant in the daisy 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 ...

. Its many common names include hitch hikers, black-jack, beggarticks, farmer’s friends and Spanish needle, but most commonly referred to as cobblers pegs. It is 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 t ...

but is widely distributed as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

in other regions worldwide including

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...

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 ...

, Australia, South America and the

Pacific Islands Collectively called the Pacific Islands, the islands in the Pacific Ocean are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of se ...

.''Bidens pilosa''.
Pacific Island Ecosystems at Risk (PIER). USFS.

Description

''Bidens pilosa'' is a branched annual

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without ...

of gracile

habit A habit (or wont as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously.

, growing up to 1.8 meters tall. It grows aggressively on disturbed land and often becomes weedy. The leaves are all oppositely arranged and range from simple to

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and i ...

in form, the upper leaves with three to five

dentate Dentate may refer to: * A species having dentition * An energy-dissipating baffle block in a spillway * An individual not being edentulous * Dentate gyrus of the hippocampus * Dentate nucleus of the cerebellum * Denticity in chemistry * Dentate l ...

, ovate-to-

lanceolate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

leaflets. The petioles are slightly winged.Flora of North America, ''Bidens pilosa'' Linnaeus, Sp. Pl. 2: 832. 1753.
/ref> The plant may flower at any time of the year, but mainly in summer and autumn in temperate regions. The flowers are small heads borne on relatively long peduncles. The heads consist of about four or five broad white ray florets (ligules), surrounding many tubular yellow

disc floret 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 ...

s without ligules that develop into barbed fruits. The fruits are slightly curved, stiff, rough black rods, tetragonal in cross section, about 1 cm long, typically with two to three stiff, heavily barbed awns at their

distal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

ends. The

infructescence Infructescence (fruiting head) is defined as the ensemble of fruits derived from the ovaries of an inflorescence. It usually retains the size and structure of the inflorescence. In some cases, infructescences are similar in appearance to simple fru ...

s form stellate spherical

bur A bur (also spelled burr) is a seed or dry fruit or infructescence that has hooks or teeth. The main function of the bur is to spread the seeds of the bur plant, often through epizoochory. The hooks of the bur are used to catch on to for exa ...

rs about one to two centimeters in diameter. The barbed spines of the achenes get stuck in the feathers, fur, fleeces, clothing, etc. of people or animals that brush against the plant. It is an effective means of

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 zoochory, as the fruits are transported by animals. This mechanism has helped the plant become a noxious weed in temperate and tropical regions. The barbed awns can injure flesh.

Distribution

The species is native to tropical America, widely naturalized throughout the warm temperate and tropical regions of the world. A weed of gardens, woodlands, and waste areas.

Common names

Its many English common names include black-jack, beggarticks, hairy beggarticks, cobbler's pegs, devil's needles, hairy bidens, Spanish needle, farmers friend, Devils Pitchfork, hitch hikers and sticky beaks.

Uses

Although ''Bidens pilosa'' is primarily considered a weed, in many parts of the world it is also a source of food and medicine.Grubben, G. J. H. & O. A. Denton. (2004) Plant Resources of Tropical Africa 2. Vegetables. PROTA Foundation, Wageningen; Backhuys, Leiden; CTA, Wageningen. The leaves have a resinous flavor, and are eaten raw, in stews, or dried for storage. It is especially important in eastern Africa, where it is known as ''michicha''. In Vietnam, during the Vietnam War, soldiers adopted the herb as a vegetable, which led to it being known as the "soldier vegetable". It is susceptible to hand weeding if small enough, even then must be bagged, and thick mulches may prevent it from growing. In

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of actio ...

, this plant is considered a

medicinal herb Medicinal plants, also called medicinal herbs, have been discovered and used in traditional medicine practices since prehistoric times. Plants synthesize hundreds of chemical compounds for various functions, including defense and protection ag ...

, called ''xian feng cao'' ().. In traditional Bafumbira medicine, this plant is applied on a fresh wound and is known as ''inyabalasanya''.. Extracts from ''Bidens pilosa'' are used in Southern Africa for malaria.

Chemistry

Almost two hundred compounds have been isolated from ''B. pilosa'', especially polyacetylenes and

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

s. The plant contains the chalcone okaninPresence of Compounds in Picao preto (Bidens pilosa).
Raintree Nutrition. and ethyl caffeate, a

hydroxycinnamic acid Hydroxycinnamic acids (hydroxycinnamates) are a class of aromatic acids or phenylpropanoids having a C6–C3 skeleton. These compounds are hydroxy derivatives of cinnamic acid. In the category of phytochemicals that can be found in food, there ...

.Chiang, Y., et al. (2005)
Ethyl caffeate suppresses NF-κB activation and its downstream inflammatory mediators, iNOS, COX-2, and PGE2 in vitro or in mouse skin.
''Br J Pharmacol.'' 146(3) 352–63.

References

External links

PROTAbase Record display for ''Bidens pilosa''

Plant Resources of Tropical Africa __NOTOC__ Plant Resources of Tropical Africa, known by its acronym PROTA, is a retired NGO and interdisciplinary documentation programme active between 2000 and 2013. PROTA produced a large database and various publications about Africa's useful ...

(PROTA). Retrieved on 12 April 2010. {{Taxonbar, from=Q814421 pilosa Flora naturalised in Australia Flora of North America Plants used in traditional Chinese medicine Plants described in 1753 Taxa named by Carl Linnaeus