Crab Cactus. This genus is confined to Brazil, so far as known, where the plants grow as epiphytes upon the trees, along with orchids, growing in large clusters on the branches: stems flat and jointed, becoming rounded with age, bearing areolae only on the margins and more or less truncated ends, from which grow the new branches and flowers.
Flowers more or less conspicuously zygomorphous: ovary devoid of bracts, and those of the tube comparatively large and colored as the petals. The genus is closely allied to Phyllocactus, and, indeed, the last two species are referred by some authors to that genus. In cultivation many forms have been produced through hybridization between the different species and with Phyllocactus and Cereus, so that typical plants are rarely met with.