The Asclepias syriaca, more commonly known as the milkweed plant, is a herbaceous plant, which is also known as Butterfly flower, silkweed, wild cotton, silky swallowwort, etc. It is found throughout the United States, in dry or swampy areas, as long as they get plenty of sunshine. It is called milkweed because it exudes a thick, sticky white sap from all its parts; stems, flowers, and leaves.