This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Closely resembles B. connata, glabrous throughout; stem branched, 1°-4° high. Leaves similar, lanceolate, sharply serrate, petioled, or the upper sessile and entire, acuminate at the apex, nar-nowed at the base; involucre narrowly or becoming somewhat broadly campanulate, its outer bracts linear, foliaceous, not ciliate, usually much exceeding the oblong inner ones; rays none, or rarely present and very short; achenes linear-cuneate, 3"-5" long, their sides and the 2 slender pappus awns (rarely with 2 short intermediate awns) upwardly barbed or hispid.
Muddy shores of the Delaware River and Bay in Pennsylvania, New Jersey, Delaware and Maryland. Aug.-Oct.
Coreopsis discoidea T. & G. Fl. N. A. 2: 339. 1842. B. discoidea Britton, Bull. Torr. Club 20: 281. 1893.
Annual, glabrous, slender, branching, erect, 2'-6° high. Leaves membranous, very slender-petioled, all the lower ones divided into 3 lanceolate or oblong-lanceolate, dentate, acuminate segments which are 1-3' long; uppermost leaves commonly rhombic-lanceolate and undivided; heads usually numerous, slender-peduncled, 2"-4" broad and about as high; involucre broadly campanulate or hemispheric, its outer bracts mostly 4, usually foliaceous and obtuse, usually much surpassing the inner ones; rays apparently always wanting; achenes flat, narrowly cuneate, upwardly strigose, about 2" long; pappus of 2 short, upwardly hispid, rarely downwardly barbed awns.
In swamps and wet places, Massachusetts to Virginia, Ohio, Michigan, Louisiana and Texas. July-Sept.
Bidens frondosa L. Sp. PI. 832. 1753. B. melanocarpa Wiegand, Bull. Torr. Club 26: 405. 1899.
Annual; stem erect, branched, glabrous, or nearly so, often purplish, 2°-3° high. Leaves thin, but not membranous, slender-petioled, pinnately 3-5-divided or the uppermost undivided, the segments lanceolate or oblong-lanceolate, sharply serrate, acuminate at the apex, narrowed at the base, usually slightly pubescent beneath, stalked, 2'-4' long, 1/2'-1' wide; heads usually numerous, long-peduncled, about 6" high, 5"-10" broad; involucre campanulate, becoming hemispheric, its outer bracts 4-8, more or less foliaceous, often much exceeding the ovate-lanceolate, scarious-margined inner ones; rays none or rudimentary and inconspicuous; disk-corollas orange; achenes flat, narrowly cuneate, nearly black, 3"-s" long, ciliate, the two slender awns downwardly barbed, or sometimes upwardly hispid.
In moist soil, often a weed in fields, Nova Scotia to Florida, British Columbia, Texas, Colorado and California. Introduced as a weed into southern Europe. Rayless marigold. Beggar-lice. Devil's-pitchfork. Stick-seed. Common bur-marigold. Old-ladies clothes-pins. Cuckles. July-Oct.