Any of the approximately 150 species of weedy, usually perennial, herbaceous plants that make up the genus Solidago, in the aster family (Asteraceae). Most are native to North America; a few grow in Europe and Asia. They have toothed leaves and clustered yellow flower heads composed of both disk and ray flowers. Characteristic plants in eastern North America, they are found almost everywherein woodlands, swamps, on mountains, in fields, and along roadsidesand are a prominent feature of autumn from the Great Plains east to the Atlantic. Unlike ragweed, which blooms at the same time, they are not a cause of hay fever.