Kalanchoe is a genus of about 125 species of tropical, succulent plants in the stonecrop family Crassulaceae, mainly native to Madagascar and tropical Africa. A Kalanchoe species was one of the first plants to be sent into space, sent on a resupply to the Soviet Salyut 1 space station in 1979. Kalanchoes require direct sunlight although they can survive with bright indirect sunlight. They only need to be watered when the soil is completely dry.

Most are shrubs or perennial herbaceous plants, but a few are annual or biennial. The largest, Kalanchoe beharensis from Madagascar, can reach 6 m (20 ft) tall, but most species are less than 1 m (3 ft) tall.

Kalanchoes open their flowers by growing new cells on the inner surface of the petals to force them outwards, and on the outside of the petals to close them.

More Info: en.wikipedia.org