In rainforests where the vegetation is dense, sunlight is scarce. Some plants have solved the problem by growing on top of other plants. The mistletoe cactus is one such epiphytic plant and grows on top of its host plant without harming it. 

The mistletoe cactus is the only cactus species that grows outside of America! In addition to America, its distribution also covers tropical Africa, Madagascar and Sri Lanka. The cactus's drought tolerance is useful in the rainforest; even though it rains a lot, the water evaporates quickly due to the warm climate. 

The mistletoe cactus is used as a houseplant and the small, sweet fruits are edible. The plant's possible use as an anti-cancer drug is under research.