Hylocereus undatus, also known as the Nightblooming cactus, is a climbing cactus that is often found trailing over rocks or as an epiphyte hanging down from branches of other plants on which is has become established. The stems of most cacti are photosynthetic therefore they are green in color due to the presence of the plant pigment chlorophyll. In succulent cacti the stems may be angled rather than round in cross-section, which allows the stem to expand slightly as water is stored in the stem. The leaves of cacti, which are not photosynthetic, are reduced to small brownish-grey spines that are found in clusters of 1-3 on the ridges of the stem. The white to yellow flowers of this species are very large, reaching 25-30 cm in length and contain many long narrow petals that make this a very striking flower. The flowers are fragrant when they open in the early evening and stay open overnight often lasting until the middle of the next day before falling. The fruit of Nightblooming cactus are oblong in shape, reaching 5-12.5 cm in length and 3.8-9.0 cm wide. The fruit is fleshy at maturity, red with fleshy green scales, and contains many small, black seeds in a juicy white pulp.