Orchid cactus blooms at night, since the flowers are predominantly pollinated by bats and large moths. They have large white star-like flowers to help their pollinators locate the blossoms by moon or star light, and many have very lovely fragrances. Pure white flowers, the size of a dinner plate, open as soon as the sun goes down and stay open all night, closing in the morning. It is a shrub growing on trees, freely branched, 2-6 m tall, with aerial roots. Old stems and basal extension shoots round, to 2 m or more, woody; branches numerous, dark green, laterally flattened, leaflike, lanceshaped to oblong-lanceshaped. Areoles small, spineless. Flowers nocturnal, fragrant, funnel-shaped. Sepaloids often recurved, pale green or pinkish red, linear to inverted-lanceshaped. Petaloids white, inverted-lanceshaped to obovate. Filaments white; anthers cream.Fruit rare, purplish red, oblong.