Purplestem Beggarticks

Bidens connata may be better treated as part of B. tripartita.

Annuals, (5–)25–150(–200) cm. Leaves: sessile or petioles (± winged) 5–15(–35+) mm; blades ± elliptic to lanceolate, (20–)40–100(–200+) × 10–30(–70) mm, sometimes laciniately 1-pinnatisect with 1–4+ lobes near bases, bases cuneate, margins entire or dentate to serrate, usually ciliate, apices attenuate, faces glabrous or hirtellous. Heads borne singly or in 2s or 3s. Peduncles 10–35(–80) mm. Calyculi of 2–6+ spreading or ascending, lanceolate, linear, oblanceolate, oblong, or spatulate, ± foliaceous bractlets or bracts 10–25(–35+) mm, margins (entire or serrate) usually ciliate, abaxial faces hispidulous near bases, distally glabrous. Involucres campanulate to hemispheric or broader, (4–)6–12 × (3–)6–9(–15+) mm. Phyllaries (6–)8(–9), elliptic to oblong or ovate, (4–)5–6(–12) mm. Ray florets usually 0, sometimes 1–5+; laminae yellowish, 4–8 mm. Disc florets (5–)20–40(–60+); corollas pale yellow to orange, 2–3 mm (± abruptly ampliate, anthers usually dark, blackish). Cypselae blackish to purplish or brown, usually (at least inner) ± 4-angled, usually cuneate to linear, sometimes ± obpyramidal, outer (3–)4–7 mm, inner (4–)5–8 mm, margins proximally antrorsely to patently, distally retrorsely, barbed, apices ± truncate to concave, faces usually strongly 1-nerved, usually tuberculate, glabrous or setulose; pappi 0, or of (1–)2–4(–6), ± erect to spreading, antrorsely or retrorsely barbed awns (0.2–)2–5 mm. 2n = 48.

Bidens connata var. ambiversa Fassett; B. connata var. anomala Farwell; B. connata var. fallax (Warnstorf) Sherff; B. connata var. gracilipes Fernald; B. connata var. inundata Fernald; B. connata var. petiolata (Nuttall) Farwell; B. connata var. pinnata S. Watson; B. connata var. submutica Fassett

Bidens connata , the purplestem beggarticks or London bur-marigold, is a species of flowering plant in the family Asteraceae. It is widespread across much of Eurasia, North Africa, and North America, and naturalized in Australia and on certain Pacific Islands.

Bidens connata is an annual herb up to 200 cm (80 inches) tall. It produces as many as 3 yellow flower heads containing both disc florets and ray florets. The species grows in marshes and other wet sites.