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A tree common in the forests of Java, and of some of the neighboring islands, and found also in tropical Africa. It is a species of the genus Antiaris (A. toxicaria), nat. order Artocarpaceae. Many exaggerated stories were formerly current concerning the deadly properties of this plant, its exhalations being said to be fatal to both animal and vegetable life at several miles distance from the tree itself. The truth is, that the upas is a tree which yields a poisonous secretion and nothing more. The active principle in this secretion has been termed antiarin.