Christmas cactus

The Christmas cactus (Schlumbergera bridgesii) is a species of epiphytic cactus in the family Cactaceae, native to the coastal mountains of southeastern Brazil. Unlike most members of the cactus family, which are adapted to arid conditions, Schlumbergera species grow as epiphytes in humid tropical forests at moderate elevations, anchored to tree branches or rocky surfaces in areas with high rainfall. The flattened, segmented stem sections are true phylloclades — modified stem tissue that performs photosynthesis. Plants produce striking tubular flowers at the tips of stem segments, typically in shades of red, pink, purple, orange, or white. In cultivation, Christmas cactus flowers around the winter holiday season in the Northern Hemisphere when exposed to long nights, making it a widely popular houseplant. Outdoors in its native habitat, flowering is triggered by seasonal changes in daylength and temperature. The flowers are pollinated by hummingbirds. The species is commonly confused with closely related species such as Schlumbergera truncata, which flowers slightly earlier and is known as the Thanksgiving cactus. In its native Brazilian habitat, the species faces pressure from ongoing deforestation of the Atlantic Forest, one of the world's most threatened biodiversity hotspots.