Original: Kumquats or cumquats are a group of small fruit-bearing trees in the flowering plant family Rutaceae, either forming the genus Fortunella, or placed within Citrus sensu lato.
Simplified: in the subgenus Fortunella of the genus Citrus in the flowering plant family Rutaceae, often seen as a separate genus Fortunella The edible fruit (which is also called kumquat) is similar to other Citrus but is smaller.