This "zygocactus" is called Easter cactus in the northern hemisphere where it flowers in the Spring and summer months. But in Australia where the spring and summer occur around Christmas it's called Christmas cactus. It's a Rhipsalidopsis whereas most "zygocacti" are now classified under Schlumbergera. Zygocactus has had no botanical validity since 1953 (although many nurseries have sold these epiphytic plants under the name zygocactus since 1953, probably because they had the labels printed and didn't want to trash them). Whatever, it provides a lot of colour.