Crossosoma californicum, known by the common name California rockflower, is one of only a few species in the flowering plant family Crossosomataceae.

It is also known from one location on the mainland California coast at the Portuguese Bend Nature Preserve, on the Palos Verdes Peninsula of Los Angeles County.

[1] Crossosoma californicum is a shrub or small tree sprawling to a maximum height of 5 metres (16 ft).

The stem is intricately divided into many thorn-tipped branches lined with veiny, pale green, oval-shaped to rounded leaves up to 9 centimeters long.

The species produces solitary flowers with round white petals, each one to 1.5 centimeters long.