Epiphyllum oxypetalum

Epiphyllum oxypetalum, the Dutchman's pipe cactus, princess of the night or queen of the night, is a species of cactus with a native range from Mexico to Nicaragua. It blooms nocturnally, and its flowers wilt before dawn. Though it is sometimes referred to as a night-blooming cereus, it is not closely related to any of the species in the tribe Cereeae that are more commonly known by that name. All Cereus species bloom at night and are terrestrial plants; Epiphyllum species are usually epiphytic....read more on Wikipedia.