Soehrensia quadratiumbonata

Soehrensia quadratiumbonata is a species of Soehrensia found in Bolivia.

Description
Soehrensia quadratiumbonata grows as a shrub with several upright branches emerging from the base, reaching heights of up to 1 meter. The cylindrical green stems are 4 to 5 cm in diameter. There are nine to twelve ribs with cross-grooves. The round, brown areoles on the ribs are about 1 cm apart, from which white, needle-like spines with brown tips emerge. Typically, there is a single, robust, 1 to 4-centimeter-long central spine, and seven to ten radial spines measuring 0.4 to 1 cm in length.

The long, funnel-shaped white flowers open at night but not fully. The dark green fruits are up to 3.5 cm long and wide.

Distribution
Soehrensia quadratiumbonata is found in the Bolivian departments of Chuquisaca and Santa Cruz at elevations of 1000 to 1900 meters.

Taxonomy
First described as Trichocereus quadratiumbonatus by Friedrich Ritter in 1980, the species name derives from the Latin words quadratus (four-sided) and umbonatus (navel-like), referring to the almost rectangular ribs of the plant. Boris O. Schlumpberger reclassified the species into the genus Soehrensia in 2012.