Dunn's mariposa lily

Calochortus dunnii is a perennial herb growing a slender, branching stem up to 60 centimeters tall. The waxy, channeled basal leaf is 10 to 20 centimeters long and withers at flowering. The inflorescence bears 2 to 6 erect bell-shaped flowers. Each flower has three sepals and three white or pinkish petals. The petals are up to 3 centimeters long and spotted with red and yellow near the bases, where there are patches of yellow hairs. The fruit is a narrow, angled capsule 2 to 3 centimeters long.

The plant is endemic to the Peninsular Ranges, native to southern San Diego County, California; and northern Baja California state, Mexico. It is known from only a few occurrences in chaparral, grassland, and Closed-cone coniferous forest habitats, at 185–1,830 feet (56–558 m) in elevation in the Cuyamaca Mountains, Laguna Mountains, and others.