Asclepias purpurascens is a perennial herb to 1 m tall; stem erect, finely hairy, sap milky.
Leaves opposite, stalk to 0.8 to 2.5 cm long, blade 10-15 cm long, elliptic to egg-shaped, finely hairy below, smooth above, base contracted.
Flowers dark purple, to 1 cm, radially symmetrical (see A. syriaca); inflorescence umbrella-shaped, one or a few flowered, at top of stem; June-July.
Fruit dry, hollow pods 10-15 cm, filled with plumed seeds, held erect, hairy but not warty.
Wetland status: FACU.
Frequency in NYC: Infrequent. Rare (NYS S3 U),
Habitat: Upland open woods, meadows.