asperula (Antelopehorns or Spider Milkweed)
Asclepias asperula grows on dry sites on the plains and or in ponderosa pine or pinyon-juniper communities in the foothills. It is found primarily from El Paso County and south, and counties along the western edge of Colorado. Leaves are long and narrow. The purple hoods and greenish petals are distinctive. Plant height is 4 to 16 inches.