Although an orchid fossil was found in rocks of the Eocene Epoch in Italy, about 45 million years old, orchids originated from the same ancestral stock as the amaryllis (Amaryllidaceae) and the lilies (Lilliaceae). Orchids are classified as part of the family Orchidaceae and are the most common type of flowering plant, in terms of number of species. Orchids constitute 7% of all flowering plants. Some taxonomists recognize as many as 35,000 species in 1,000 genera. They are found all over the world, in all climates, from the Arctic to the tropics, but not in the desert. The vast majority are tropical or subtropical and can be found growing in the wild.