Hymenothrix wislizeni, the Trans-Pecos thimblehead, is a North American species of flowering plant in the daisy family. It grows in northwestern Mexico (Baja California, Sonora, Chihuahua) and the southwestern United States (far western Texas, Arizona, New Mexico).Hymenothrix wislizeni is am annual herb up to 70 cm (28 in) tall. Each head has 15-30 yellow or cream-colored disc flowers surrounded by 8-12 yellow ray flowers.