What is the X in X-mas?
any of six areas of the world recognized by plant geographers for their distinctive plant life. These regions, which coincide closely with the faunal regions (q.v.) as mapped by animal geographers, are often considered with them as biogeographic regions. The chief difference is the recognition by plant geographers of the Cape region of South Africa as a distinct major unit because of its rich flora, which includes more than 1,500 genera, 30 percent of which are native nowhere else in the world