Proceeding southward cacti become common, first a dwarfed species, and then a larger columnar form (Cereus quisco).
In ascending from the coast-valleys there is first an arid range, where the great-branched cacti rear themselves up among the rocks.
The vegetation on the western side of the island is much less dense, often appearing as scattered clumps of trees on savannah-like plains rather than continuous forest; while in the south-west, where the rainfall is very scanty, the vegetation is largely of fleshy-leaved and spiny plants - aloes and cacti (the latter introduced), with several species of Euphorbia, as well as numerous lianas, one of which (Intisy) yields india-rubber.
Giant cacti and spiny scrub abound.
The most common plants of the Mexican plateau are the agaves, yuccas and cacti, each of which is represented by a number of species.