Calochortus

Calochortus, commonly known as mariposa lilies, is a genus of perennial herbaceous plants in the family Liliaceae. The genus is native to western North America, with the greatest diversity in the United States and northern Mexico. These flowering plants are characterized by bulbs that produce a single, erect stem bearing a sparse inflorescence of typically one to three bell‑shaped or nodding flowers. The corolla is often bright, exhibiting blue, lavender, white, or yellow hues, sometimes with distinctive veining or spotting. The petals are growable and can be reflexed or slightly bowed, while the sepals are more rigid.

The genus includes well over a hundred recognized species, ranging from the small, cryptic Calochortus bellii of the Sierra Nevada to the larger, showy Calochortus fremontii of the Southwest. Many species have adapted to specific habitats, such as dry, sandy soils, moist meadows, or rocky slopes. The lifecycle of Calochortus is often tightly linked to seasonal moisture patterns; they typically germinate in late winter or early spring, flower in late spring to early summer, and then enter dormancy.

Calochortus species are prized in horticulture for their ornamental value. They are grown in rock gardens, native plant displays, and spring color beds. The bulbs are often propagated by division or seed sowing, though many species are difficult to maintain outside their native microclimate. Conservation concerns arise for several rare species, especially those with limited geographic ranges or those disturbed by development and invasive plants. Several Calochortus species are also fragments of the flora of traditional east Asian ceremonies and were historically used in folk medicine, although modern use is limited primarily to ornamental cultivation.