Plants 6–20 dm, glabrous, glaucous or not.
Leaves 10–35 cm, thin, glabrous but occasionally with scattered hairs on veins on underside; leaflets lanceolate to ovate, (2)3–11 cm.
Inflorescences peduncles 10–45 cm; rays 10–60, 2–9 cm; involucel bractlets 0(1–3), inconspicuous; pedicels 1–7 mm.
Flowers ovaries hairy.
Fruits oblong to ovate, 5–10 mm.
2n=22.
Wet meadows, roadsides, wooded areas. Flowering Jun–Aug. 0–1000 m. CR, Est. CA. Native.
Contrary to the name, no parts of this plant are tomentose. See also A. arguta discussion.