any of three genera of weedy plants in the family Asteraceae, all native to North America. Some species in each genus have reflexed ray flowers. Purple-flowered perennials of the genus Echinacea, especially E. angustifolia and E. purpurea, often are cultivated as border plants. They have strong-smelling black roots, hairy stems, and basal leaves on long leafstalks.

Plants of the genus Ratibida have yellow ray flowers, brownish disk flowers, and segmented leaves. Prairie coneflower (Ratibida columnaris) and R. pinnata are grown in wildflower gardens. The third genus, Rudbeckia, has about 25 annual, biennial, and perennial species with simple or segmented leaves, yellow ray flowers, and brown or black disk flowers. black-eyed Susan (R. hirta), thimble-flower (R. bicolor), and coneflower (R. laciniata) are grown as border plants. Golden glow (R. laciniata variety hortensia) is a popular double-flowered variety.