Coreopsis calliopsidea is a species of flowering plant in the daisy family known by the common name leafstem tickseed. It is endemic to California where it grows in some of the southern coastal mountain ranges and the Mojave Desert. This is an annual herb producing one or more stems with erect flower clusters growing up to about 40 centimeters tall, or sometimes taller. The slighly fleshy leaves are located mainly around the base of the stem, each divided into several narrow lobes. The flower cluster bears a single flower head with a bell-shaped involucre of triangular phyllaries. The head has a center of up to 50 tiny yellow disc florets and a fringe of usually 8 bright yellow ray florets each up to 3.5 centimeters long. The fruit is an achene. The fruit of the ray floret is oval and hairless and lacks a pappus; that of the disc floret is more slender, shiny, lined with hairs, and tipped with a pappus of scales.