Kumquats are a group of small fruit-bearing trees in the flowering plant family Rutaceae. Their taxonomy is disputed. They were previously classified as forming the now-historical genus Fortunella or placed within the genus Citrus, sensu lato. Different classifications have alternatively assigned them to anywhere from a single species, C. japonica, to numerous species representing each cultivar. This photograph, depicting one halved and two whole kumquats, was focus-stacked from 22 separate images.Photograph credit: Ivar Leidus