×Citrofortunella

thumb|Citrofortunella varieties (left to right): Jiangsu kumquat, calamansi, limequat, mandarinquat Citrofortunella are a large group of commercial hybrids that cross the kumquat with other citrus. In the system of citrus taxonomy established by Swingle, kumquats were placed in a different genus, Fortunella, from Citrus, which included citron, mandarin orange, pomelo and papedas. The result of genetic crosses between kumquats and these other citrus would then be intergeneric hybrids, so a novel genus name was coined for them in 1975, by compounding the names of the contributing genera to form Citrofortunella. That the genus is of a hybrid nature is represented by a multiplication sign before the genus name, for example × Citrofortunella microcarpa. Recent phylogenetic work has shown kumquats to fall within Citrus rather than belonging to a distinct genus, meaning these would no longer be considered intergeneric hybrids, and use of Citrofortunella as a distinct genus name for these hybrids loses taxonomic validity. All would be placed instead within Citrus.

These hybrids combine some of the edibility properties of the more typical Citrus species with the cold hardiness of the kumquats, often being referred to as cold hardy citrus. They produce small acidic fruit and are also more compact than other citrus, making them good ornamental plants.