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Comprising a land area of ca. 90,000 km(2), less than one twentieth (5%) file land area of the southern African subcontinent, the Cape Floristic Region (CFR) is, for its size, one of the world’s richest areas of plant species diversify. A new synoptic flora for the Region has wade possible an accurate reassessment of the flora, which has an estimated 9030 vascular plant species (68.7% endemic), of which 8920 species are flowering plants (69.5% endemic). The number of species packed into so small all area is remarkable for the temperate zone and compares favorably with species richness for areas of similar size in the wet tropics. The Cape region consists of a mosaic of sandstone and shale substrata with local areas of limestone. It has a highly dissected, rugged topography, and a diversity of climates with rainfall mostly falling in the Winter months and Varying from 2000 non locally to less than 100 mm. Ecological gradients are sleep as a result of abrupt differences in soil, altitude, aspect, and precipitation. These factors combine to form an unusually large number of local habitats for plants. Sandstone-derived soils have characteristically low nutrient status, and many plants present oil such soils have low seed dispersal capabilities, a factor promoting localized distributions. An unusual family composition includes Iridaceae, Aizoaceae, Ericaceae, Scrophulariaceae, Proteaceae, Restionaceae, Rutaceae, and Orchidaceae among the 10 largest families in the flora, following Asteraceae and Fabaceae, as the most speciose families. Disproportionate radiation lids resulted in over 59.2% species falling in the 10 largest families and 77.4% in the largest 20 families. Twelve genera have more than 100 species and the 20 largest genera contribute some 31% of the total species. Species richness of the Cape flora is hypothesized to lie the result of geographic and parapatric radiation in all area with a mosaic of different habitats line 10 local soil, climate, and altitudinal differences that combine to produce steep ecological gradients. Also contributing to the diversity has been a relatively stable geological history since the end of the Miocene that saw the establishment of a semi-arid and extreme seasonal climate at the southwestern part of southern Africa.