Excerpt From Book
The Cape Floral Region is a botanical anomaly. Not only does it have more plant species than would be anticipated given its latitude and climate, it is also home to far more bulbous plants than anywhere else in the world. Its flora is in fact so singular in many respects that the region is classified as one of the world's six floral kingdoms. This is truly remarkable given the unusually small area occupied by the Cape Floral Region, only 0.04% of the earth's land surface. The other floral kingdoms, in comparison, occupy all or most of one or more continents.
Elsewhere in the world the number of plant species per unit area increases form temperate to tropical latitudes and from arid or semiarid habitats to well-watered ones. The Cape Floral Region defies these trends. Although it lies well within the temperate zone and most of it experiences a semiarid climate of low annual rainfall and summer drought, it is nevertheless home to about 9000 plant species in an area of only 90,000 square kilometers (35,000 square miles). This is more species than the species-rich, wet tropics of Panama, which covers a comparable area, and only slightly fewer than in Costa Rica, another tropical area of comparable size. Comparisons between the floras of regions with a Mediterranean climate, which characterizes much of the Cape Floral Region, only emphasize the remarkable richness of the Cape flora. California, for instance, which is recognized as having a rich and diverse flora, actually only supports about 5000 species (just over half the number found in the Cape flora) in an area more than three times larger than the Cape Floral Region. Another peculiarity of the Cape flora is its remarkably high level of endemism. Almost 70% of the species in the Cape flora are found nowhere else on earth. This level of endemism is characteristic of isolated oceanic islands and is unique for a continental flora.
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