The Avocado

• Today's avocado is a descendant of fruit grown on trees that originated in south-central Mexico, according to the California Avocado Commission. The Spanish conquistadors named the fruit "aguacate," which evolved into avocado. The fruit is a staple of California's agricultural economy, where it grows year-round. An avocado tree can produce up to 500 pieces of fruit each year, but the average is 150. San Diego County is home to 60 percent of California's avocado industry; 6,000 farmers have 60,000 acres under cultivation. The "Haas" variety of avocado is California's major variety. Its fruit is ovoid with a wrinkled skin that turns black as the avocado ripens. Its flesh is a soft, creamy green and pale yellow with a single large seed in its center. The flesh of the fruit forms the base for guacamole.
  
  

Mexican Guacamole

• The concept of guacamole was developed by the Aztecs, who prized the avocado, with its high fat content, as a valuable addition to their low-fat diet. Although their recipe is lost, today's basic guacamole recipe contains foods grown widely in Central America. The Spanish Conquistadors contributed the white onion, a root vegetable, to the mix. Tomatoes, fruits of a vine that originated in the Peruvian Andes, added flavor and volume to the mixture. To this, the Mexicans added spice and heat with cumin and Serrano or Jalapeno peppers. Sea salt helps combine the flavors.
  
  

Keep it Green

• Avocado fruit oxidizes rapidly and turns dark. Citric acid controls this process, so juice from the fruit of the lime tree is often added to guacamole to maintain its soft green color. Culantro -- the leaf of the tropical perennial herb Eryngium foetidum -- is another native seasoning. Recipes often substitute its close relative, cilantro.
  
  

Adaptations

• As guacamole recipes traveled around Central America and the Caribbean -- places where avocado trees grow easily -- each ethnic group added its own familiar ingredients. The juice of the fruit of the lemon tree may substitute for lime. Cajun red pepper, cayenne and thyme give the dish a more Caribbean flavor. Garlic, a root that is related to the onion, is a common addition. Sometimes, hot pepper sauce, white pepper and even olive oil and olives are added to the mix. For the truly adventurous, the California Avocado Commission even offers a recipe that includes goat cheese and pistachio nuts.