Holiday cacti are known for their colorful tubular flowers and ease of care. They include Christmas, Thanksgiving and Easter cacti. Christmas cacti have flattened leaves with rounded teeth on the margins as opposed to the Thanksgiving cactus that has pointed teeth. Easter cacti have pointed teeth with fibrous hairs in the leaf joints. Under normal conditions the holiday cacti will bloom close to the holiday suggested in its name. Florists will often force plants into bloom at other times. To make things really confusing, most of the Christmas cactus sold are actually Thanksgiving cactus and will bloom in subsequent years at Thanksgiving time. So don't be surprised if the plant you bought last year at Christmas time is blooming now.
http://web.extension.illinois.edu/cfiv/homeowners/111122.html
http://web.extension.illinois.edu/cfiv/homeowners/111122.html