Senna barclayana, commonly known as smooth senna or pepper-leaf senna,[1] is a species of flowering plant in the family Fabaceae and is endemic to eastern Australia. It is a herbaceous perennial or subshrub with pinnate leaves with six to ten pairs of lance-shaped or narrowly elliptic leaflets, and yellow flowers in groups of six to ten.
Senna barclayana is an erect, herbaceous perennial subshrub that typically grows to a height of up to . Its leaves are pinnate, long on a petiole long, with six to ten pairs of lance-shaped or narrowly elliptic leaflets long and wide. There is a sessile gland near the base of the petiole, and a stipule that falls off as the leaf opens. The flowers are yellow and arranged in upper leaf axils in pairs or groups of six to ten on a peduncle long, each flower on a pedicel long. The petals are up to long and there are six fertile stamens and four staminodes, the longest anthers about long. Flowering occurs all year, and the fruit is a cylindrical pod long.[2] [3]
This species was first formally described in 1827 by Robert Sweet who gave it the name Cassia barclayana in his Flora Australasica.[4] [5] In 1988, Barbara Rae Randell transferred the species to Senna as Senna barclayana in the Journal of the Adelaide Botanic Garden.[6] The specific epithet (barclayana) honours Robert Barclay of Bury-hill (1751–1830).[7]
Senna barclayana grows in open forest southern Queensland and northern New South Wales, but its range is increasing and it is now naturalised in Victoria, South Australia and Western Australia.[8]