1.  milkweed(n = noun.plant) silkweed - any of numerous plants of the genus Asclepias having milky juice and pods that split open releasing seeds with downy tufts;
is a kind of herb, herbaceous plant
is a member of asclepias, genus asclepias
has particulars: asclepias albicans, white milkweed, asclepias curassavica, blood flower, swallowwort, asclepias exaltata, poke milkweed, asclepias incarnata, swamp milkweed, asclepia meadii, asclepias meadii, mead's milkweed, asclepias purpurascens, purple silkweed, asclepias speciosa, showy milkweed, asclepias subverticillata, horsetail milkweed, poison milkweed, asclepias tuberosa, butterfly weed, chigger flower, chiggerflower, indian paintbrush, orange milkweed, pleurisy root, tuber root, asclepias verticillata, whorled milkweed

2.  milkweed(n = noun.plant) sonchus oleraceus - annual Eurasian sow thistle with soft spiny leaves and rayed yellow flower heads;
is a kind of milk thistle, sow thistle

   Any plant of the genera Asclepias and Acerates, abounding in a milky juice, and having its seed attached to a long silky down; silkweed. The name is also applied to several other plants with a milky juice, as to several kinds of spurge. Its leaves are a favorite food source for the larvae of the monarch butterfly. [1913 Webster]

milkweed, n. any of various wild plants with milky juice.

horsetail milkweed, marsh milkweed, mead's milkweed, milkweed butterfly, milkweed family, orange milkweed, poison milkweed, poke milkweed, showy milkweed, swamp milkweed, white milkweed, whorled milkweed