It is endemic to California, where it is known from the chaparral and woodlands in the Sierra Nevada foothills, from Madera to Kern Counties.

Leptosiphon serrulatus is a plant of woodlands, chaparral, and yellow pine forests.

It is a small annual herb producing a thin, hairy stem up to about 18 centimeters tall.

The leaves are divided into linear lobes up to a centimeter in length.

The inflorescence is a head of small flowers, each with a purplish tube almost a centimeter long and a white corolla.