    thumb|milkweed sprout, a few days after sowing  asclepias l. (1753), the milkweeds, is a genus of herbaceous perennial, dicotyledonous plants that contains over 140 known species. it previously belonged to the family asclepiadaceae, but this is now classified as the subfamily asclepiadoideae of the dogbane family apocynaceae. milkweed is named for its milky sap, which consists of a latex containing alkaloids and several other complex compounds including cardenolides.singh, b. and rastogi, r.p. (1970). cardenolides-glycosides and genins. phytochemistry 9: 315-331. some species are known to be toxic. carl linnaeus named the genus after asclepius, the greek god of healing, because of the many folk-medicinal uses for the milkweed plants. pollination in this genus is accomplished in an unusual manner. pollen is grouped into complex structures called pollinia (or "pollen sacs"), rather than being individual grains or tetrads, as is typical for most plants. the feet or mouthparts of flower-visiting insects such as bees, wasps and butterflies, slip into one of the five slits in each flower formed by adjacent anthers. the bases of the pollinia then mechanically attach to the insect, pulling a pair
Asclepias Plants_with_dehiscent_fruit Poisonous_plants