SCHLUMBERGERA

cactus genus of three species, family Cactaceae, native to Brazil, grown for its striking elongated flowers, unique in the family and adapted to pollination by hummingbirds. All grow perched on trees or shrubs, sometimes in shady places among rocks. S. russelliana and S. truncata (long known as Zygocactus) have short flattened stem segments. The common Christmas cactus (q.v.; S. bridgesii), blooming about Christmas time in the Northern Hemisphere, may be a hybrid of these two. The two remaining species, S. opuntiodes and S. obtusangula, have rounded stem segments but similar flowers. The species formerly called Schlumbergera gaertnerai, the spring-flowering Easter cactus (q.v.), is now placed in the genus Rhipsalidopsis.