Bidens pilosa

About

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, and is classified as an invasive species in some regions of the world.

Summary from Wikipedia