Angelica atropurpurea is a perennial herb, taprooted, stout, stem solitary, hollow, to 2 m tall, 3 cm diameter at base, purplish or purple-blotched.
Leaves alternate, pinnately compound, basal leaves 10-30 cm long, often twice compound, 5-7 leaflets about 4-10 cm long, egg-shaped to lanceolate, tip pointed, margin sharply toothed, small veins extend to tips of teeth, leaves progressively reduced upwards, petioles elongate, conspicuously veined, inflated, sheathing the stem, to 5 cm wide with prominent veins.
Flowers white to greenish, radially symmetrical, small, 5 parted, inflorescence 10-20 cm wide, of twice umbrella- shaped clusters (compound umbel) with 20-45 rays, secondary umbels densely flowered June- Aug.
Fruit dry, 0.4-0.6 cm wide oblong to elliptic, 2-seeded, the seeds separating at maturity (schizocarp), sides broadly winged, sharply ridged; July-Oct.
Wetland status: OBL.
Frequency in NYC: Very infrequent.
Habitat: Open marshes, wet edges. Apiaceae of open sites are eaten by larvae of the black swallowtail butterfly, Papilio polyxenes (Papilionidae); (Tallamy 2003; Pyle 1981).