Sesamum radiatum Schumach. & Thonn. is a flowering plant that belongs to the family Pedaliaceae and is the same genus as sesame (S. indicum), known in Malay as bijan. Sesamum is derived from the Greek word sesamon while radiatum is coined from the Latin word radiare meaning radiating which refers to the straight ribs that radiate from the centre of the seed. The species has its origins in Africa (Bedigian, 2004) and is reported to be distributed in Malesia from Peninsular Malaysia to Sumatra and Borneo (Sabah and Sarawak). In Malaysia, this species was first recorded in 1885 from Melaka. It appears to have been naturalized, as has occurred with S. indicum throughout Peninsular Malaysia (Yao, 2010).
Commonly known as Black sesame, Black benniseed and English wild benniseed (Burkill, 1985), S. radiatum is a hairy erect herbaceous plant that can grow to 1.2 m tall. The leaves are simple, opposite, mainly ovate, deep green in colour with sunken veins on the upper surface that are alternately arranged towards the top of the plant. The petioles are about 0.5–3.4 cm long. The bell-shaped flower has a pink to purplish corolla, sometimes white, produced solitarily at the leaf axils and measure up to 3.0 cm long and 1.5 cm wide. The fruit is cylindrical, erect and dull green, up to 3.2 cm long and contains brown or black seeds roughly 3.0 mm long and 2.0 mm wide (Yao, 2010).
In Peninsular Malaysia, this species can be found at roadsides and in abandoned tin mining areas. The plants are usually overrun by ants, probably attracted by the extra-floral nectaries. It leaves a strong foetid smell when crushed (Yao, 2010). Sesamum radiatum resembles S. indicum in habit, but it can be distinguished by its testa structure which has sub-horizontal ribs compared to smooth reticulate ornamentation in the latter.
Most people in Malaysia do not know the uses of this species. It is one of the many neglected and underutilized leafy vegetables despite its numerous nutritional benefits. Sesamum radiatum with its high protein, vitamin and mineral content can be a good supplement to the predominantly starchy diets of the people of the tropics. It also has several medicinal and cosmetic uses.
