Heterodistyly inOldenlandia scopulorum Bull., a member of the Rubiaceae, is described. The species is characterised by two floral forms, the pin with long style and short anthers and thrum with short style and long anthers. Further the pin has small pollen grains and long stigmatic papillae while the thrum has large pollen grains and short stingmatic papillae. Pollination experiments with pin and thrum forms in compatible and incompatible crosses are reported. Pin self is compatible while thrum self incompatible. The cross pin x thrum is more fertile than thrum x pin.