Bidens pilosa is an annual forb of gracile habit, growing up to 1.8 meters tall. It grows aggressively on disturbed land and often becomes weedy. The leaves are oppositely arranged and pinnate in form with three to five dentate, ovate-to-lanceolate leaflets. The petioles are slightly winged. The plant may flower at any time of the year, but in temperate regions it blooms mainly in summer and autumn. Flowers are borne in small heads on relatively long peduncles. The heads bear about four or five broad white ray florets, surrounding many tubular yellow disc florets. The fruits are slightly curved, stiff, rough black rods, tetragonal in cross section, about 1 cm long, with typically two to three stiff, heavily barbed awns at their distal ends. The infructescences form stellate spherical burrs about one to two centimeters in diameter. The barbed awns catch onto fur or clothing, and can injure flesh. 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.
Description: Erect herbs, stem quadrangular. Leaves opposite, 12-18 cm, pinnate; lobes to 6×3 cm, ovate-lanceolate, apex acute, base truncate, serrate, hairy. Heads to 1 cm across; peduncles to 8 cm, fl exuous, involucral bracts biseriate, outer ca. 3×1 mm, linear, spathulate, inner to 5×2 mm, ovate, obtuse. Rays fl orets 2-5. Corolla bilobed, yellow; disc fl orets many. Achenes many ca. 2.5 mm; setae 2-4, ca. 3 mm long.
Hairy beggarticks 's Behavior & Ecology
Resident of infertile open wastelands and disturbed areas in native regions. Widely naturalized throughout world as pantropical and crop weed.
Hairy beggarticks 's Relationship with Humans
Edible Plant Parts (Edible Flowers; Edible Stems; Edible Leaves) Food (Fruit & Vegetable; Herb & Spice) Edible Plant Parts (Edible Flowers; Edible Stems; Edible Leaves), Medicinal
Food: Plant is a good source of iodine, and has peppery or spicy taste. Tender leaves cooked as vegetable by poor people. Leaves added raw to salads or steamed in soups and stews. Young shoot tips brewed as tea. Flowers served with rice dishes.
Medicinal: Plant has anti-inflammatory, bactericidal and fungicidal properties. Juice of plants applied to minor fresh wounds & ulcers, or used to treat thrush and rheumatism. Also used in enemas for intestinal ailments.