appearance black seeds cactus fruit climbing cactus colorful colors colourful colours contrast cultivated decorative dragon fruit exotic food fruit green hylocereus undatus ornamental plant pitahaya pitaya red red skin shape shapes Sizes smell strawberry pear tasty textures white flesh black-seeds cactus-fruit climbing-cactus dragon-fruit hylocereus-undatus ornamental-plant red-skin seeds seedy size strawberry-pear surface surfaces texture textured white-flesh cactus edible juicy moist pips produce red-flesh succulent-plant unusual