A cactus is a member of the plant family Cactaceae, within the order Caryophyllales. The plural of cactus varies; the Latin cacti, the English cactuses and the uninflected plural cactus are all used. Cacti have a variety of uses: some species are used as ornamental plants, others are grown for fodder or forage, others for food (particularly their fruit). Cochineal is the product of an insect that lives on some cacti.