The Osagawara Islands are oceanic islands that are located 1000 km south of Tokyo in the northwestern Pacific Ocean.
Three island groups are present that contain up to 30 islands that have a subtropical flora. The basal rocks of the Ogasawara Islands may have formed up to 45 million years ago, although the current emergent islands are probably only several million years old. The islands have two rainy seasons, the first from May to June and the second from October to November and a dry season during the height of summer from July to August. The islands contain 330 native vascular plants, two native terrestrial vertebrates (a fox bat and a lizard), 11 extant land birds, 800 insects, and 100 land snails. Forty percent of the vascular plants are endemic to the Osagawara Islands, meaning this is the only location in the world where those species are found.
(Shimizu, Y. 2003. The nature of Ogasawara and its conservation. Global Environmental Research 7:3-14.)