Tachibana orange
The tachibana orange is a variety of mandarin orange, a citrus fruit. It is native to China and introduced to Japan 2000 years ago. The Tanaka System assigns it to its own species, while the Swingle System places it in the same species with other mandarin oranges. Genomic analysis has shown it to be genetically pure, without the pomelo introgression found in the closely related domesticated mandarin oranges of mainland Asia, though distant enough for it to by considered a distinct subspecies by Wu, et al.. They are estimated to have diverged from other Asian mandarins about 2 million years ago, and likely spread to the islands over land bridges formed during Pleistocene glacial maxima, probably arising near where its mandarin cousins would later be domesticated in the Nanling Mountains of China.
