Bidens pilosa is a species in the plant family Asteraceae, called Spanish Needle. It is regarded as a weed in some tropical habitats. But in some parts of the world it is a source of food.Bidens pilosa is found along waysides and ditches. It is an erect annual with pinnately divided leaves. There are 5 or 6 white rays and a yellow disc. The achenes are shaped like harpoons with two awns at the top. The two awns have backward pointed barbs, while the body of the achene has forward pointing barbs.