Bidens pilosa L., it is an annual herb, hairy to almost glabrous, up to 100 cm tall. branched. Leaves petiolate; petiole narrowly ‘winged. imparipinnate with I (-2) pairs of petiolate lateral pinnae and a large terminal one; pinnae broadly lanceolate to ovate-lanceolate. acuto-acuminate, coarsely toothed; principal veins dark coloured; teeth apices obtuse-acuminate; under-surface of leaf often with white, transluscent crystals. Capitula discoid or radiate with ray florets white or cream coloured, long pedunculate, in lax corymbose panicle, 5-15 mm in diam. Involucre slightly hairy at the base; outer involucral bracts 5-8, 6-7 x 2-2.25 mm. oblanceolate to obovate, herbaceous-green, with dark, thick mid-nerves, obtuse; inner involucral bracts slightly smaller or nearly equalling the outer ones, ovate, darkish with a greenish or whitish scarious margins, acute. Palea 4-5 mm long, linear, acute, dark coloured with broad. scarious, whitish margins. Ligules (when present). 8-10, 1-rowed, white or cream coloured, sterile. Disc florets yellow. Cypsela 6-8 (-12) mm, fusiform, papillose, with few erect setae on the ribs and near the apex; apex with scarious. brownish corona and 2-3, retrosely barbellate, erecto-patent bristless.
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