It is a biennial herb with tuberous and paired roots. The mother root is often dry and cylindrical and the daughter root varies from shortly conical to long cylindrical. Its external surface is generally smooth and light brown. The leaves are orbicular-cordate to reniform with a very wide shallow sinus. Flowers are greenish blue in few-flowered panicles. The follicles are 2.5 to 3.0 cm long. The seeds are blackish, obovoid, obscurely winged along the raphe and transversely lamellate.