In prehistoric times montane forest covered one third of the land of present-day Rwanda. Naturally occurring vegetation is now mostly in the three National parks, with terraced agriculture in the rest of the country. Nyungwe, the largest remaining forest, has 200 species of tree as well as orchids and begonias. Vegetation in the Volcanoes National Park is mostly bamboo and moorland, with small areas of forest. Akagera has a savanna ecosystem. Here there are mostly acacia. There are several rare or endangered plant species in Akagera, including "Markhamia lutea" and "Eulophia guineensis".