ABSTRACT
The area of origin of the olive was the Laurophyllus forest around the Thetys. The Tertiary Mediterranean basin was inside a tropical zone, but partial basin drying out and Pleistocene glaciation were strong natural selection criteria for a sclerophyllous plant with moderate freezing avoidance characteristics. Olive trees may grow to a considerable size, but a slow growth rate and longevity are characteristics of the species. The terminal growing apices are dominant and repress axillary bud development in a basipetal direction; however apical dominance is influenced by irradiance, soil fertility and growth regulators. The strong dominance of a leader shoot inside a branch can originate 'decurrent' or 'excurrent' forms. Light fluence is a very important factor for olive flower induction. Olive leaves are bifacial and morphologically heterogeneous. The adaxial surface of the leaf is noticeably darker than the abaxial surface. Olive has developed adaptations to environmental stress consistent with evolution in a Mediterranean climate.
