Harrisia tetracantha

Harrisia tetracantha is a species of cactus found in Bolivia.

Description
Harrisia tetracantha grows in a shrub-like to tree-like manner, is usually branched above the ground and reaches heights of up to 3 meters. The blue-green to gray-green shoots have a diameter of up to 6 centimeters. There are eight rounded and tuberous ribs. The single, strong, initially brownish central spine later becomes white to ash-gray. The four to seven white marginal spines have a brown tip.

The flowers reach a length of 18 to 22 centimeters.

Distribution
Harrisia tetracantha is widespread in the Bolivian departments of Cochabamba, Chuquisaca, Potosi, Santa Cruz and Tarija in dry scrub forest at elevations of 1200–2600 meters.

Taxonomy
The first description as Cereus tetracanthus was made in 1855 by J. Labouret. David Richard Hunt placed the species in the genus Harrisia in 1987. Further nomenclature synonyms are Eriocereus tetracanthus (Labour.) Riccob. (1909), Trichocereus tetracanthus (Labour.) Borg (1937), Roseocereus tephracanthus (Labour.) Backeb. (1942), Roseocereus tetracanthus (Labour.) Backeb. (1942) and Echinopsis tetracanthus (Labour.) Anceschi & Magli (2013).