Christmas cacti result from crosses of Schlumbergera truncata (Thanksgiving cactus) and S. russelliana. Although flower colors include purple, pink, white, red, orange, or yellow, Christmas Cactus can be identified by the oblong or obovate stem segments with crenate (round-teethed) margins.
Easter cacti result from crosses of Hatiora gaertneri and H. rosea. The flowers are intermediate between those of its parents and seen in a range of colors. The leaves are characteristically oblong to narrowly oblanceolate. Notice the shallowly crenate (round-teethed) to nearly non-existent lobes on the stem segment margins and the areoles with fine, brown bristles.
Thanksgiving cactus' oblong stem segments become pendulous with length. Note the sharply serrate-dentate (coarse, forward-pointing teeth) along the stem segment margins. Flower color is typically rose to red.