Morphological variation in tribe Hylocereeae. A Aporocactus martianus (Photo S. Avendaño) B Disocacus ackermannii (Photo C. Ruiz) C Kimnachia ramulosa subsp. ramulosa (From Flora de Nicaragua, O.M. Montiel) D Selenicereus atropilosus (From Hunt 2006) E Epiphyllum hookeri (Photo C. Ruiz) F Pseudorhipsalis amazonica (From Mobot - Hammel 24524) G Acanthocereus tetragonus (Photo C. Gómez-Hinostrosa) H Selenicereus (Hylocereus) undatus (Photo C. Ruiz) I Weberocereus tunilla (From Mobot – B. Hammel 22442).