Lithospermum ruderale is a species of flowering plant in the borage family known by the common name western stoneseed or lemonweed.

A perennial herb growing from a taproot and woody caudex, it is covered with fine, more or less upright, hairs, especially on the stems.

It produces a cluster of erect leafy stems ranging from 20 to 50 centimetres (7+7⁄8 to 19+5⁄8 in) centimeters in height.

The corolla is fused at the base with five lobes[2] which are light yellow, often slightly greenish, and about a centimeter long and wide.

The plant was used as a contraceptive by several Native American groups, including the Navajo and Shoshone.