Plants terrestrial to epiphytic, vinelike, clambering, pendent. Roots frequently aerial and adventitious. Stems bluish green to purple, to 100-300 × 2.5-5 cm; ribs 4-6, acute; areoles 2-2.5 cm apart along ribs, 1.5-3.0 mm. Spines 1-5, short conic (acicular on immature stems), 1-3 mm; radial and central spines not distinguishable. Flowers 25-30 × 20 cm; outer tepals brown or purplish (or yellow-), narrow; inner tepals white, oblanceolate, apex acute; areoles of ovary and flower tube bearing numerous scales and long, white, hairlike spines. Fruits red, spheric, 45-70 mm diam., hidden by short (to 1 cm), yellowish, bristlelike spines and long, white hairlike spines. 2n = 22. Flowering year-round. Disturbed coastal sites; 0-10 m; introduced; Fla.; Mexico. Selenicereus pteranthus is widely cultivated for its showy, fragrant flowers and occasionally escapes. The species is reported from six counties in Florida, where it is presumed naturalized.