Pleurisy (Asclepius tuberosa) is a bushy, 1 1/2-2 ft. perennial prized for its large, flat-topped clusters of bright-orange flowers. The leaves are spirally arranged, lanceolate, 5–12 cm long, and 2–3 cm broad. The yellow-orange to bright orange flower clusters, 2-5 inches across, are at the top of the flowering stem.