Annuals (biennials), (15-)30-50(-150+) cm. Leaves: petioles 5-20+ mm; blades ± deltate to ovate overall, 40-75(-150) × 10-45(-130) mm, usually laciniately 1-2-pinnatisect, ultimate lobes (3-)5-7+, oblanceolate or lanceolate to linear, (5-)10-30(-80+) × (1-)4-8(-12+) mm, bases cuneate, ultimate margins incised, dentate, serrate, or entire, little, if at all, ciliate, apices acute to attenuate, faces glabrous or ± hirtellous to strigillose. Heads usually in open, ± corymbiform arrays. Peduncles 20-150 mm. Calyculi of (6-)8(-11), ascending to spreading, spatulate to linear, sometimes ± foliaceous bractlets or bracts 3-10(-18) mm, margins sometimes ciliate, abaxial faces glabrous. Involucres hemispheric or broader, 4-6(-8) × 6-12 mm. Phyllaries 6-8(-10), oblong, 3-8 mm. Ray florets (7-)8-9; laminae golden yellow, 10-30 mm. Disc florets 40-60(-80+); corollas yellow, 3-5 mm. Cypselae blackish or brown, flattened, narrowly cuneate, outer 3-6 mm, inner 5-9 mm (lengths mostly 2.5-4 times widths), margins antrorsely barbed or ciliate, apices ± truncate, faces obscurely 1-nerved, sometimes tuberculate, glabrous or sparsely hispidulous; pappi of 2 erect, ± patently barbed awns or scales (0.4-)1-2.5(-4) mm. 2n = 24. Flowering Aug-Oct. Marshes, estuaries; 0-300 m; Ont., Que.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Iowa, Ky., Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., S.Dak., Tenn., Va., W.Va., Wis. Plants here called Bidens trichosperma have long been known as B. coronata (Linnaeus) Britton (or Britton ex Sherff). Alas, Britton´s B. coronata (1913) is a later homonym of B. coronata Fischer ex Colla (1834) and cannot be used.