Bourbon is the most famous of the Bourbon-descended varieties (see History of Bourbon and Typica for a full history of this group of coffees). It is a tall variety characterized by relatively low production, susceptibility to the major diseases, and excellent cup quality.
French missionaries introduced Bourbon from Yemen to Bourbon Island (now La Réunion)—giving it the name it has today—in the early 1700s. Until the mid-19th century, Bourbon did not leave the island. But beginning in the mid-1800s, the variety spread to new parts of the world as the missionaries moved to establish footholds in Africa and the Americas.
The Bourbon variety was introduced to Brazil around 1860, and from there rapidly spread north into other parts of South and Central America, where it is still cultivated today. Here it became mixed with other Bourbon-related varieties, introduced from India as well as Ethiopian landraces. Nowadays, there are many Bourbon-like varieties found in East Africa, but none exactly match the distinct Bourbon variety that can be found in Latin America.
Today in Latin America, Bourbon itself has largely been replaced by varieties that descend from it (notably including Caturra, Catuai, and Mundo Novo), although Bourbon itself it is still cultivated in El Salvador, Guatemala, Honduras, and Peru.