A herb. The roots have fleshy tubers near the tips. It also has stolons or creepers. The leaves are narrow. They are 7-20 cm long by 2-3 cm wide. They have 5 veins. There are many sheaths around the base. The flowers occur singly, but sometimes are in clusters of 2 or 3. The flowers are purplish. The seeds are dark blue at maturity. They are 4-5 mm across.