Avocado The Aztecs also cultivated the avocado(they called it ahuactl) The avocado is an oily fruit, rich in vitamins A, B, and C. The fruit does not get ripe on the tree. People need to pick it from the tree before it develops its flavor and full maturity. Sailors used to call avocados "seaman's butter," because the fruit lasts for a long time and it was good for sea voyages.