The genus Calpurnia, commonly known as the African laburnum, is a small group of shrubs and trees in the Fabaceae. The plants are recognised by their distinctive pea-shaped yellow flowers and flat seed pods, known as legumes. The genus name was given by the German botanist Ernst Heinrich Friedrich Meyer (E. Mey.), he named it after the Roman poet, T. Julius Calpurnius. The name was chosen because plants in the genus Calpurnia are closely related to and thus similar to those in the genus Virgilia, which was named after the Roman poet Virgil, and it was thought that Calpurnius imitated Virgil’s work. The names of the two plant genera therefore reflect their close botanical relationship. Most Calpurnia species are endemic to southern Africa, one species, Calpurnia aurea, the best-known species, is more widespread with a wide distribution, occurring in southern, eastern and central Africa, as well as parts of southern India. Calpurnia sericea (mountain calpurnia), which is closely related to Calpurnia reflexa, occurs in grassland and among rocks in the Eastern Cape, Free State, KwaZulu-Natal, Mpumalanga and in Lesotho and Eswatini; and Calpurnia woodii (woolly calpurnia), is also a rare species with a limited distribution that occurs in bushveld and grassland in KwaZulu-Natal.

The species name reflexa is a Latin word meaning ‘bent backward’ or ‘turned back’, which describes backward-curving lobes of the calyx which is unique in Calpurnia. The common name Free State Golden-pea refers to the plant’s occurrence in the Free State province and its bright golden-yellow flowers, which resemble those of pea plants. Sotho Laburnum refers to the plant's occurrence in regions traditionally associated with the Sotho people and its resemblance to European laburnum trees, which produce hanging clusters of bright yellow flowers.