I’m more familiar with the crab cactus under its popular name of Christmas cactus. It’s fuchsia-like flowers, which are typically crimson, appear around Christmas.
The crab cactus is a hybrid which often goes under the name Zygocactus. One of its parents, Schlumbergera truncata, is a native of the coastal mountains of south-east Brazil, near Rio de Janeiro. It is an epiphyte, growing on trees, or a lithophyte, growing on rocks.