"Over 50 relict monotypic genera have survived from the Mesozoic era, 20% of China's total, among them the dove tree Davidia involucrata, Katsura tree Cercidophyllum japonicum, Chinese money maple Dipteronia sinensis, dawn redwood Metasequoia glyptostroboides (CR), Chinese bretschneidera Bretschneidera sinensis (EN), gingko Gingko biloba (EN), Tetracentron sinensis and one-eyed grass Kingdonia uniflora. 50 genera are endemic to China (20% of its total) and 67 plant species are nationally protected."