Avocado or alligator pear (because of its rough skin) (Persea americana) originated in south-central Mexico and has been cultivated for centuries by the Incas in Peru and throughout Mexico.  Avocado is a modified Aztec word for testicle because of the shape of the fruit.  Since 1871, 90% of U.S. avocados have been cultivated in California. U.S. growers are now facing competition from Mexico and Chile because of the North American Free Trade Agreement (NAFTA). 

Avocados belong to the botanical family Lauraceae, a tropical and subtropical family. Sassafras and avocado originated in the Western Hemisphere. The plants that produce cinnamon, camphor, and bay leaves, originated in the Eastern Hemisphere.  Avocado has inconspicuous flowers that open and close at different times depending on whether they are accepting pollen (acting as a female) or releasing pollen (acting as a male). This helps keep the plants from self-pollinating and increases genetic diversity in the species. Commercial plantings use grafted trees and rootstocks to give consistent fruit types. The trees produce as many as 200 fruit each year.

Avocados are berries with a fleshy layer between the tough outer skin and the seed.  Some biologists have speculated that the huge seeds may have been swallowed whole and later excreted by now-extinct giant mammals such as the South American ground sloths or gomphotheres (elephant-like animals).  Humans benefit from eating the nutritious layer surrounding the seed which contains potassium, vitamin E, B-vitamins, folic acid, and lutein. Although avocados are one-third fat, it is monosaturated, a good kind. There are reports that avocados are poisonous to some pet animals.

One way to banish winter blues is to have a tropical plant growing in your house. It is not difficult to germinate an avocado seed. You can suspend it, pointy end up, with toothpicks in water so the seed is about half covered. You can also plant the seed in soil.  The resulting plants can become very large but do not usually produce fruit.

Image Credits:

http://www.plantsciences.ucdavis.edu/gepts/pb143/crop/avocado/avocado.gif

http://www.botanicalfeast.com/wp-content/2006/03/avocado2.jpg