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Distribution of Diversity

Plants occur over most of the earth's land surface, but the distribution of species is distinctly uneven. Distribution is affected by environmental factors including climate, soils, and topography. Knowing the distribution of species enables scientists to establish criteria and guidelines for their conservation and ecologically sustainable use.

Botanists have collected the most data on plant species found in countries with relatively low diversity. Britain's flora has probably been studied more extensively and been better inventoried than that of any other country, while in many tropical countries, only a handful of botanists are studying tens of thousands of plants. Often, once a plant has been named or described, it is not seen again for years. Almost nothing is known about the distribution of immense numbers of tropical plants.

Continent Plant Species
Central & South America 85,000
Tropical & Subtropical Africa 40,000–45,000
North Africa 10,000
Tropical Africa 21,000
Southern Africa 21,000
Tropical & Subtropical Asia 50,000
India 15,000
Malaysia 30,000
China 25,000
North America 18,000
Europe 12,500