Of the world's six floral kingdoms, this is the smallest and richest per unit of area. The Holarctic kingdom, in contrast, incorporates the whole of the Northern Hemisphere north of the tropics. The diversity of fynbos plants is extremely high, with over 9,000 species of plants occurring in the area, around 6,200 of which are endemic, i.e. growing nowhere else in the world. South Africa's Western Cape has the vast majority of species with one estimate finding 8,550 species in 89,000 km2, which is higher than that estimated for the Malayan forests, 7,900 species in 132,000 km2. It has been claimed that it exceeds even the richest tropical rainforest in South America, including the Amazon. Of the Ericas, over 600 occur in the fynbos kingdom, while only two or three dozen have been described in the rest of the world. This is in an area of 46,000 km2 - by comparison, the Netherlands, with an area of 33,000 km2, has 1,400 species, none of them endemic. Table Mountain in Cape Town supports 2,200 species, more than the entire United Kingdom. Thus, although the fynbos covers only 6% of the area of southern Africa, it has half the species on the subcontinent - and in fact has almost 1 in 5 of all African plant species so far described.