Sub-category: Milkweed family
A perennial wildflower, grows from 2 to 6 feet tall and usually unbranched. The central stem is light green to purplish green, terete, and glabrous. Opposite pairs of leaves about 3 to 8 inches long and 1 to 3 inches across; they are lanceolate-elliptic to ovate and smooth along their margins. Both the tips and bottoms of the leaves are wedge-shaped, rather than rounded. The upper leaf surface is medium to dark green and glabrous, while the lower surface is pale to medium green and glabrous (or nearly so). The leaves are widely spreading and remain more or less the same size along the stem. The distinct petioles are 0.5 to 2 inches long and light green. The foliage contains a milky latex.
The stem terminates in one or more umbels of flowers spanning 2 to 4 inches across. The umbels are relatively open and the flowers droop somewhat from their pedicels. Each flower is about 0.25 inches across and 0.5 inches long, consisting of 5 petals that hang downward, 5 curved cylindrical hoods that surround a central column, and the reproductive organs. The insignificant sepals are hidden by the petals. Each hood has an exerted horn. The flowers are bicolored: the petals are green or pale purple, while the hoods and column are white or light pink. During the fall, each seedpod splits open along one side to release its seeds. The seeds have tufts of hair at their apices.
Found in moist woodland habitats. It grows in moist soil and sunny or partly shaded places. Blooms June to August.