Koeberlinia spinosa Zucc.

Nomenclature and Native Range

Koeberlinia spinosa Zucc. is a species of flowering plant native to the southwestern United States and northern Mexico. It has several common names: crown of thorns, allthorn, smokebush, and crucifixion thorn.

Taxonomic Classification

It is one of two species in the genus Koeberlinia, which is sometimes classified as the only genus in the plant family Koeberliniaceae. Alternately, the genus is treated as a member of the caper family.

Size and Growth Form

This is a moderate to large sprawling shrub that reaches a maximum height over 4 m (13 ft). When actively growing, the entire plant is green, and it is composed of many tangling, straight, heavily branched stems.

Stem and Spine Characteristics

The tip of each rigid stem branch tapers to a long, sharp spine. Its leaves are mostly underdeveloped, growing as tiny deciduous scales.

Photosynthetic Structure

Most photosynthesis is carried out by the green stem branches.

Flower Characteristics

The shrub produces abundant blooms that are white to greenish-white.

Fruit Characteristics

Its fruits are shiny black berries, each a few millimeters long, and these berries are attractive to birds.

Mexican Plateau Distribution

Koeberlinia spinosa occurs in northern regions of the Mexican Plateau, extending east down to the northern foothills of the Sierra Madre Orientals.

Western Range Distribution

To the west, its range extends into the southern and central Sonoran Desert of Sonora, and southern and southwestern Arizona. It also grows in three areas of Baja California Sur, which are part of the Sonoran Desert.