Description from Flora of China
Cereus subg. Hylocereus A. Berger, Rep. (Annual) Missouri Bot. Gard. 16: 72. 1905.
Plants climbing, scrambling, or epiphytic. Stems branched, usually 3-winged or -angled, margins often horny, often producing numerous aerial roots. Areoles spaced far apart in notches along wings or angles. Spines short or rarely absent. Leaves absent. Flowers usually nocturnal, white or rarely red, funnelform, large. Receptacle tube usually elongate, stout, with broad, leaflike scales. Stamens numerous, inserted in receptacle tube and perianth throat, shorter than perianth. Placentas parietal; stigmas numerous, sometimes 2-fid or flabellate. Fruit globose, ellipsoid, or ovoid, large, fleshy, spineless, with broad scales. Seeds numerous, ovate-reniform; testa glossy black, smooth or minutely spotted.
About 15 species: from Mexico and the West Indies to South America; four species cultivated in China, of which one species naturalized in southern areas.