any of various plants of the genus Vernonia of tropical and warm regions of especially North America that take their name from their loose heads of purple to rose flowers that quickly take on a rusty hue
Any of about 500 species of perennial plants constituting the genus Vernonia (family Asteraceae). Small herbaceous (nonwoody) species are found throughout the world; shrubs and trees are found primarily in tropical regions. Ironweed species have lance-shaped, toothed leaves that alternate along the stem; clusters of flower heads composed only of disk flowers (no ray flowers); and a ring of overlapping bracts below the flower heads. Some autumn-blooming species are cultivated as border plants for their attractive white, purple, or pink flower clusters