Summary
The hypothesis that the more exposed the strata of a tree, the more xeric the conditions and thus the more xeroscleromorphic the structure of the leaves was here tested using Pogonophora schomburgkiana. It was found that from the base to the canopy of the tree, the number of stomata/mm2 increased, the mesophyll became thicker, and the leaves decreased in size, these among other characters, that indicate xerophylly. All of these character changes support the hypothesis tested.