Note: Information is dated. Do not rely on it.Cactus. A Linnaean genus of plants, now used as a name for any of the Cactaceae, a natural order of dicotyledons, otherwise called the Indian fig order. The species are succulent shrubs, with minute scale-like leaves (except in the genus Pereskia, tree cactus, with large leaves) , or with bristles and spines on the stems instead of leaves. They have fleshy stems, with sweetish watery or milky juice, and they assume many peculiar forms. The juice in some species affords a refreshing beverage where water is not to be secured. All the plants of this order, except a few African species, are natives. of America, They are generally found in very dry localities. Several have been introduced into the old world, and in many cases they have become naturalized. The fruits of some species are edible. The flowers are usually large and beautifully colored, and many members of the order are cultivated in hothouses.