Etymology - The name means "before cereus" - after the Latin Prae.
This genus is comprised of two species that are widespread in South America and the island of Trindad. The plants are shrubby, sprawling, cylindrical stems with 7 or more ribs. Spines are needle-like and number between 7 and 20 and not especially thick or dense. Funnel-shaped flowers on a stout floral tube with scales, but no spines are white or greenish-white; nocturnal. Fruits are red and elongated - fleshy.