Aztekium

An Aztekium with distinct ribs and a more elevated stem than A. ritteri. Internally, the wood remains without fibres, while the cortex and pith remain parenchymatous.

A small, grey-green cactus with ribs divided into dense transverse folds. Most of its surface lies in the shade of its own stem, while stomatal apparatuses cluster in depressions whose opening changes with tissue hydration.

An Aztekium species with a small number of main ribs, described from Nuevo León in 2013.