Calotropis procera is a species of flowering plant in the family Apocynaceae that is native to North Africa, tropical Africa, Western Asia, South Asia, and Indochina. The green fruits contain a toxic milky sap that is extremely bitter and turns into a gluey coating which is resistant to soap. Common names for the plant include Apple of Sodom, Sodom apple, stabragh, king's crown, rubber bush, and rubber tree. The name Apple of Sodom and Dead Sea Apple comes from the fact that the ancient authors Josephus and Tacitus described it as growing in the area of biblical Sodom.