Principally of the genus Asclepias in order Gentianales, family Apocynaceae
A monarch butterfly (Danaus spp).
Euphorbia peplus and Euphorbia heterophylla, in order Malpighiales.
Also of the genus Calotropis in order Gentianales, family Apocynaceae
Any plant of the genus Asclepias whose seed vessels contain a long, silky down; milkweed.