.Streblus asper is a tree known by several common names, including Siamese rough bush, khoi, serut, and toothbrush tree. It is a medium-sized tree native to dry regions in Indonesia, Cambodia, Thailand, India, Sri Lanka, Malaysia, and Vietnam.The leaves are approximately 5–10 centimetres (2–4 inches) long, rigid, oval-shaped, irregularly toothed, and borne on small petioles. Staminate flower heads are spherical with minute flowers; pistillate flowers have longer peduncles.