Alicyclobacillus hesperidum is a species of Gram positive, strictly aerobic, bacterium. The bacteria are acidophilic and produced endospores. It was first isolated from solfataric soils in the Furnas, the Azores. The species was first described in 2000, and the name refers to the Hesperides, mythological figures whom the Greeks believed to have lived at the Western edge of the Earth in a miraculous garden, which [the researchers] interpret as the Azores.