Asclepias

Asclepias is a genus of over 100 species of deciduous or evergreen, clump-forming or spreading perennials and shrubs from scrub, grassland, marsh, or lakeside in temperate North America, tropical North and South America, and South Africa with elliptic to ovate, sometimes spirally-arranged leaves and cymes of flowers with upright, horn-like appendages followed by paired, green fruit that ripens yellow-brown.