The supplemental map shows the plant regions color-coded by the contributions they make to the total numbers of plant endemics -- those found nowhere else. The scale is cumulative. For example, Colombia in South America, combined with areas that are warmer colored -- Ecuador, Panama, and Costa Rica -- has more than seven endemic plant species per 1,000 square kilometers in a sample of 100,000 plant species.
[Image courtesy of L. Joppa, P. Visconti, C.N. Jenkins, S.L. Pimm]