Perideridia oregana is a species of flowering plant in the family Apiaceae known by the common names Oregon yampah and eppaw.[1] It is native to Oregon and California in the western United States, where it grows in woodland and other habitat. This plant is quite variable in appearance. In general, it is a perennial herb 10 to 90 centimeters tall, its green to waxy-grayish erect stem growing from a cluster of small tubers. Leaves near the base of the plant have blades 3 to 30 centimeters long divided into a variable number of leaflets, which may be subdivided into smaller segments. The inflorescence is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, oblong-shaped fruits 3 to 6 millimeters long.