The avocado is a tree native to Mexico and Central America, classified in the flowering plant family Lauraceae. The tree grows to 20 metres, with alternately arranged, evergreen leaves, 1225 centimetres long. The flower are inconspicuous, greenish-yellow, 510 millimetres wide. Avocado fruits have a smooth, creamy, greenish-yellow flesh with an unusually high amount of fat that is primarily monounsaturated. They also contain a high concentration of dietary fiber, vitamins and potassium. The pit, seed, leaves, bark and in some cases fruit can be toxic to some animals, particularly birds, though much less so in humans; the toxicity of the fruit may be an adaptation that assisted seed dispersal by Pleistocene megafauna.