Note: Do not rely on this information. It is very old.
Upas TreeUpas Tree, the native name of Antiaris toxicaria, a very poisonous artocarpaceous tree of Java, about which many fabulous stories were circulated during the last century. It grows sometimes in the dormant volcanic craters of the island, where the exhalation of the heavy and suffocating carbon dioxide kills insects, fish, birds, tigers, and even man -- effects attributed to the tree. It's milky latex, however, is caustic, acrid, and poisonous, being known as antiar to the Javanese. It dries, on incisions made in the bark, into the gum-resin known as upas, with which the natives poisoned their arrows and cris.
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