Hatiora gaertneri

About

Rhipsalidopsis gaertneri, synonyms Schlumbergera gaertneri and Hatiora gaertneri, is a species of epiphytic cactus which belongs to the tribe Rhipsalideae within the subfamily Cactoideae of the Cactaceae. Together with the hybrid with R. rosea, Rhipsalidopsis × graeseri, it is known, in English speaking countries in the Northern Hemisphere, as Easter cactus or Whitsun cactus and is a widely cultivated ornamental plant. It has received the Royal Horticultural Society's Award of Garden Merit.

Summary from Wikipedia