Glabrous annual 3–8 dm; lvs thin, trifoliolate, on petioles 1–6 cm, the lfls (or at least the terminal one) petiolulate, lanceolate to lance-ovate, serrate, acuminate, the terminal one the largest, to 10 × 4 cm; heads numerous, small, discoid, the disk 3–10 mm wide; outer invol bracts 3–5, linear-spatulate, leafy, much surpassing the disk, scarcely or not at all ciliate-margined; achenes narrowly cuneate, short-hairy, 3–6 mm; pappus of 2 antrorsely setose awns to 2 mm, or nearly obsolete; 2n=24. Wet places; n. N.S., s. Que. and Minn., s. to D.C., Ala., Okla., and Tex. Aug., Sept.