Machaeranthera asteroides (fall tansyaster) is a North American species of plants in the sunflower family. It is native to the southwestern United States (California, Arizona, Nevada, New Mexico, Colorado, Utah) and northern Mexico (Chihuahua, Sonora, Baja California). Machaeranthera asteroides is a biennial or perennial herb with a woody taproot. It often grows in a clump of several stems. Ray florets in the flower heads are white or purple, and female. Disc florets are yellow and bisexual.