The main subfamily of Cactaceae. Plants highly variable in habit, treelike, shrubby, caespitose, climbing, or epiphytic, from 1 cm up to 20 m high. Reproductive zones usually undifferentiated, sometimes differentiated or specific cephalium produced. Leaves absent, rarely vestigial. Glochids absent. Spines usually present, rarely absent. Flowers sessile, diurnal or nocturnal; 1 - 30 cm in diameter, white, yellow, orange, red, purple, pink, brown. Blue coloured flowers absent. Fruits usually fresh, berrylike, seeds small, 0,1 - 2 mm large.