Bull Torrey Bot. Club 20: 281. 1893.
Annuals, 10–90+ cm. Leaves: petioles 10–25 mm; blades lanceolate to lance-linear, 40–160 × 3–30+ mm, bases cuneate, margins entire or laciniate to serrate or denticulate, minutely, if at all, ciliate, apices acuminate to attenuate, faces glabrous. Heads usually borne singly, sometimes in open, ± corymbiform arrays. Peduncles 10–30 (–60+) mm. Calyculi of 3–5 usually spreading, narrowly lanceolate to oblanceolate, sometimes foliaceous bractlets or bracts 10–30 (–60) mm, margins entire, usually ciliate, abaxial faces usually glabrous. Involucres narrowly campanulate to cylindric, 9–16 × 5–8 (–12) mm. Phyllaries 4–8+, ± oblong, 9–16 mm. Ray-florets usually 0, sometimes 3–5+; laminae yellowish, 2–10 mm. Disc-florets 6–20 (–30+); corollas yellowish, 3–6 mm. Cypselae redbrown, flattened, sometimes weakly 4-angled, narrowly cuneate to linear, outer 6–10 mm, inner 8–13 mm, margins evenly antrorsely strigillose, apices truncate, faces smooth or ± striate, ± evenly antrorsely strigillose; pappi of 2 (–4) erect to spreading, antrorsely barbed awns (2–) 3–9 mm.
Phenology: Flowering Sep.
Habitat: Borders of streams, estuaries
Elevation: 0–10+ m
Del., Md., N.J., N.Y., Pa.