This is Schlumbergera, commonly called Christmas Cactus, because it flowers in winter. What is it called in southeast Brazil, where it occurs in the wild?
Flor de Natal (Christmas flower)
Flor de Dezembro (December flower)
Flor de Maio (May flower)
Flor de Papai Noel (Father Christmas Flower)
In Brazil, the genus is referred to as Flor de Maio (May flower), reflecting the period in which they flower in the Southern hemisphere.