Summary
The results presented in this paper in which anatomical comparisons are made between diploid and poliploid leaves of Paullinia cupana (Guaraná) are similar to those obtained by the same authors for Hevea. There is a general increase in cell size of most of the poliploid tissues which causes an increase in the thickness of the mesophyll. These characters have been considered as more xeric. The fact that no differences were found between epidermal cell sizes and size and number of stomata per unit area when comparing diploids and poliploids makes it impossible to predict drought tolerance of the poliploids as compared to the diploids.