megadiverse countries endemic species vascular plants flowering plants mammal birds reptiles amphibians insect Alaska Hawaii
The U.S. is one of 17 megadiverse countries containing large numbers of endemic species: about 17000 species of vascular plants occur in the contiguous United States and Alaska, and more than 1800 species of flowering plants are found in Hawaii, few of which occur on the mainland. The United States is home to 428 mammal species, 784 birds, 311 reptiles, and 295 amphibians, and 91000 insect species.
