Strophocactus

A shrubby cactus of the Brazilian caatinga, formerly treated in Pseudoacanthocereus. It bears slender stems and tuberous roots. Plastid DNA analysis grouped it with the other members of the Strophocactus lineage.

Ostolaza, Pino & M.Fernández

A cactus from northern Colombia and northwestern Venezuela with a shrubby habit, tuberous roots and variable stems. Some stem sections become strongly flattened. Plastid data indicated a close relationship with Strophocactus wittii.

This Amazonian epiphyte attaches thin stems to tree trunks within the seasonal flood zone. Its white flower opens for a single night. The seeds contain air chambers that keep them afloat and allow them to reach other trees.