Bidens pilosa is an annual species of herbaceous flowering plant in the daisy family Asteraceae. 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 but is widely distributed as an introduced species in other regions including Eurasia, Africa, Australia, South America and the Pacific Islands, Bidens pilosa. Pacific Island Ecosystems at Risk (PIER). USFS. and is classified as an invasive species in some regions of the world.
The plant may flower at any time of the year, but mainly in summer and autumn in temperate regions. The flowers are small pseudanthium borne on relatively long peduncles. The heads consist of about four or five broad white ray florets (ligules), surrounding many tubular yellow 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 ends.
The form spherical 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 by zoochory, as the fruits are transported by animals. This mechanism has helped the plant become a noxious weed in temperate and tropical regions.
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 it must be bagged, and thick mulches may prevent it from growing.
Extracts from Bidens pilosa are used in Southern Africa for malaria.
Distribution
Common names
Uses
Chemistry
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