These plants have high levels of endemism (i.e. species which are found only within Kinabalu Park and are not found anywhere else in the world). The orchids are the best-known example with over 800 species including some of the highly valued "Paphiopedilum" slipper orchids, but there are also over 600 species of ferns (more than the whole of Africa's 500 species) of which 50 are found nowhere else, and the richest collection in the world for the "Nepenthes" pitcher plants (five of the thirteen are found nowhere else on earth) which reach spectacular proportions (the largest-pitchered in the world being the endemic "Nepenthes rajah"). The parasitic "Rafflesia" plant, which has the largest single flower in the world, is also found in Kinabalu (particularly "Rafflesia keithii" whose flower grows to in diameter), though blooms of the flower are rare and difficult to find. Meanwhile, another "Rafflesia" species, "Rafflesia tengku-adlinii", can be found on the neighbouring Mount Trus Madi and the nearby Maliau Basin.