Distribution: Some 30 to 200 or more genera, depending on the author, and at least 1000 to maybe 2000 species; native to temperate and tropical regions of the New World, especially in warm, dry places. These stem-succulents have spines, and typically a widely spreading shallow root system adapted to take advantage of light rains in their desert habitat.
The tropical spinelss epiphytic cactus Schlumbergera is the Thanksgiving or Christmas Cactus.
