Lomatium vaginatum, known by the common name Broadsheath Desertparsley, is a species of flowering plant in the Carrot Family (Apiaceae). It is native to Northern, Central, and Southern California, and on the Modoc Plateau into Oregon and Nevada. Habitats it grows in include sagebrush, yellow pine woodlands, oak woodland, and grassy slopes.
Broadsheath Desertparsley is a perennial herb growing up to 18 inches (45 cm) tall, from a thick taproot. The leaf blades are divided and subdivided into narrow segments. Leaves higher on the stem are enclosed in sheaths. The inflorescence is an umbel of yellow flowers.