Rhipsalis baccifera

Rhipsalis baccifera, the mistletoe cactus, is an epiphytic cactus that grows on other plants rather than in soil. It originates in Central and South America, the Caribbean and Florida, but it is also found across the tropics of Africa and into Sri Lanka, which makes it the only cactus that occurs naturally outside the Americas. Two explanations are offered for this unusual range: that migratory birds carried it to the Old World long enough ago for the populations there to be treated as distinct subspecies, or that it crossed the Atlantic on European trading ships between South America and Africa and was then spread more widely by birds. The species is very variable and is divided into numerous subspecies; Mesoamerican plants are usually tetraploid while South American plants are diploid. Its genus belongs to the tribe Rhipsalideae, whose genera, including Hatiora, Lepismium and Schlumbergera, were clarified by Wilhelm Barthlott and Nigel Taylor in 1995.