Saigon cinnamon is a variety of cassia, which means that it is a close relative of Ceylon cinnamon but with a few very different qualities. While the name would seem to indicate that Saigon cinnamon is from the Saigon region in the southern part of Vietnam, it is actually native to the northern and central part of the country. The species also grows in China and Japan.
The Latin name for Saigon cinnamon is Cinnamomum loureiroi though it is sometimes written incorrectly as loureirii. It is named for Joao de Loureiro, a Portuguese botanist who was at one time a missionary in Goa and who has a large number of species named in his honor. He also described Vietnamese flora in detail.