Hymenopappus radiatus, the ray hymenopappus, is a North American species of flowering plant in the daisy family. It grows in the State of Arizona in the southwestern United States. Hymenopappus radiatus is a perennial herb up to 45 cm (18 in) tall. One plant produces 6-8 flower heads per stem, each head 8 white ray flowers surrounding 30–50 yellow disc flowers.