[3] Nicholas Edward Brown,[4] the botanist who first formally described the species, named it after its purple (purpureus in Latin) flowers.

[5] It is herbaceous to slightly woody climbing plant that reaches 4–5 meters in height.

It has ridges between adjacent petioles which sometimes have multicellular secretory hairs called colleters at their base.

Its flowers have 5 oval to narrowly triangular sepals that are 1.5–2 by 1–2 millimeters, with pointed to blunt tips and sparsely fringed margins.

The corona has fleshy oval feet that are fused with base of the petals and can have thread-like lobes that are 0.5 millimeters long.

The pistils have 1–1.3 millimeter long, hairless styles shaped like thin tapering cylinders.

The fruit occur as singles or in pairs and are tapering, oval cylinders that are 6–7.5 by 9–10.4 centimeters.