Blackstonia perfoliata is annual plant with small yellow flowers and unusual leaves, which are arranged in pairs, the two leaves are fused together giving the appearance of a single leaf perforated by the stem.

It is described as a medicinal plant and an extract of the upper parts of the plants can be used as a yellow dye.

The scientific genus has been named after John Blackstone, a botanist and apothecary of 18th century London.