All forms of plant life that live in a particular geographic region at a particular time in history. A number of factors determine the flora in any particular area, including temperature, sunlight, soil, water, and evolutionary history. The flora in any given area is a major factor in determining the type of fauna found in the area. Scientists have divided the earth's surface into a number of regions inhabited by distinct flora. Among these regions are the African-Indian desert, western African rain forest, Pacific North American region, Arctic and Sub-arctic region, and the Amazon.