Bidens bipinnata L.

Linnaeus, C. von (1753) Species Plantarum 2: 832. Type: Habitat in Virginia.

Beggar's Ticks; Beggarticks; Bipinnate Beggar's Ticks

Annual herb, but occasionally reaches a shrub of 1-1.6 m tall.

Twigs or stems 4-angled in transverse section. Leaf blades about 3.5-17 x 2-3.8 cm, very variable, usually bipinnatifid or bipinnate, rounded-deltoid to ovate or lanceolate in outline.

Flowers borne in heads 5-10 mm diam., 30-40 flowers per head. Outer involucral bracts linear to narrowly lanceolate, not dilated, 3-5(-7) mm long, glabrous or with fine hairs. Inner bracts linear-lanceolate, usually deep purplish brown, glabrous or finely hairy. Ray florets (0)3-5, yellow; ligule 1-2(-3) mm long.

Each fruit or nutlet ending in 2-3(4) plumes each with downward pointing hairs which adhere to clothes, animal fur, etc. Fruits about 9-26 mm long. Seeds (achenes) about 6-18 mm long. Embryo about 6-8 mm long, cotyledons about 2/3 of the length of the embryo. Cotyledons wider than the radicle.

Features not available, but similar to Bidens subalternans.

A cosmopolitan species of uncertain origin, now naturalised in WA, NT, CYP, NEQ, CEQ and southwards to south-eastern Queensland and north-western New South Wales. Altitudinal range from near sea level to 600 m. Grows in monsoon forest, vine thickets and other vegetation types.

This species may have some medicinal uses.