The kumquats or cumquats are a group of small fruit-bearing trees in the genus Fortunella related to the Citrus in the flowering plant family Rutaceae, often segregated as a separate genus, Fortunella. The edible fruit (which is also called kumquat) closely resembles that of the orange (Citrus sinensis) but is smaller and is often oval.

They are slow-growing, evergreen shrubs or small trees, from tall, with dense branches, sometimes bearing small thorns. The leaves are dark glossy green, and the flowers pure white, similar to other citrus flowers, borne singly or clustered in the leaf-axils. The kumquat tree produces 80 to 100 fruit each year. The tree can be hydrophytic, and fruit is often found floating near the shore during the kumquat season.

Kumquats originated in China (they are noted in literature dating to the 12th century), and have long been cultivated there and in Japan. They were introduced to Europe in 1846 by Robert Fortune, collector for the London Horticultural Society, and shortly thereafter into North America. Originally placed in the genus Citrus, they were transferred to the genus Fortunella in 1915, though subsequent work (Burkill 1931, Mabberley 1998) favours their return to inclusion in Citrus.

Four or five species are currently accepted:

• Fortunella crassifolia (syn. Fortunella crassifolia) - Meiwa Kumquat. Generally eaten fresh, skin-on, instead of cooked.
• Fortunella hindsii (syn. Fortunella hindsii) - Hong Kong Kumquat
• Fortunella japonica (syn. Fortunella japonica, C. margarita, F. margarita) - Marumi or Nagami Kumquat. Tart, prized for staying fresh on the tree longer, generally cooked or peeled.
• Fortunella obovata (syn. Fortunella obovata) - Jiangsu or Fukushu Kumquat
• Fortunella polyandra (syn. Fortunella polyandra) - Malayan Kumquat

Kumquats readily hybridise with other members of the genus Citrus and with the closely related Poncirus. These hybrids are known as Citrofortunella; examples include the limequat, orangequat, and calamondin.

In appearance the kumquat fruit (generally called simply "kumquat") resembles a miniature oval orange, long and wide. Depending on variety, peel colour ranges from yellow to red. A Nagami kumquat has an oval shape, while a Marumi kumquat is round.

Kumquat fruit is generally in season from late autumn to mid-winter, and can be found in most food markets with other produce.

Cultivation and uses

Kumquats are cultivated in China, Taiwan, Southeast Asia, Japan, the Middle East, Europe (notably Corfu, Greece), and the southern United States (notably Florida)

They are much hardier than other citrus plants such as oranges. The 'Nagami' kumquat requires a hot summer, ranging from 25 to 38°C (77 to 100°F), but can withstand frost down to about without injury. It grows in the tea balls of China where the climate is too cold for other citrus fruits, even the Mikan (also known as the Satsuma) orange. The trees differ also from other Citrus species in that they enter into a period of winter dormancy so profound that they will remain through several weeks of subsequent warm weather without putting out new shoots or blossoms. Despite their ability to survive low temperatures, as in the vicinity of San Francisco, California, the kumquat trees grow better and produce larger and sweeter fruits in warmer regions.

Propagation

Kumquats are rarely grown from seed as they do not do well on their own roots. In China and Japan they are grafted onto the trifoliate orange (Poncirus trifoliata). This has been found the best rootstock for kumquats in northern Florida and California and for dwarfing for pot culture. For this reason they are often known as "Dwarf Fruit". Sour orange and grapefruit are suitable rootstocks for southern Florida. Rough lemon is unsatisfactory in moist soils and tends to be too vigorous for the slow-growing kumquats.

Uses

Kumquats are frequently eaten raw. As the rind is sweet and the juicy centre is sour, the raw fruit is usually consumed either whole, to savour the contrast, or only the rind is eaten. The fruit is considered ripe when it reaches a yellowish-orange stage, and has just shed the last tint of green. The Hong Kong Kumquat has a rather sweet rind compared to the rinds of other citrus fruits.

Culinary uses include: candying and kumquat preserves, marmalade, and jelly. Kumquats appear more commonly in the modern market as a martini garnish, replacing the classic olive. They can also be sliced and added to salads. A liqueur can also be made by macerating kumquats in vodka or other clear spirit.

The Cantonese often preserve kumquats in salt or sugar. A batch of the fruit is buried in dry salt inside a glass jar. Over time, all the juice from the fruit is extracted through dehydration into the salt. The fruit in the jar becomes shrunken, wrinkled, and dark brown in color, and the salt combines with the juice to become a dark brown brine. A few salted kumquats with a few teaspoons of the brine/juice may be mixed with hot water to make a remedy for sore throats. A jar of such preserved kumquats can last several years and still keep taste.

In Taiwan, kumquats are a popular addition to both hot and iced tea.

In Vietnam, kumquat bonsai trees are used as a decoration for the Tết (New Year) holiday.

Variants of the kumquat are grown specially in India.

Etymology

The English name "kumquat" derives from the Cantonese pronunciation gam1 gwat1 (given in Jyutping romanization; ). The alternate name 柑橘, also pronounced gam1 gwat1 in Cantonese (gān jú in Mandarin, literally "large tangerine orange") is now more commonly written by Cantonese speakers.

Names in other Asian languages include:

• Japanese: kinkan (金柑)
• Korean: geumgyul (금귤, 金橘)
• Hokkien: gīm-gam ()
• Mandarin: jīnjú (金橘)
• Nepali: muntala
• Thai: somchíd (ส้มจี๊ด)
• Vietnamese: cam quất (derived from the Cantonese) or, less commonly, (quả) kim quất (if transliterated from the characters 金橘 into Sino-Vietnamese; "quả" (果) is the Sino-Vietnamese prefix for "fruit")

References and external links

• Kumquat culture on CultureSheet.org
• Burkill, I. H. (1931). An enumeration of the species of Paramignya, Atalantia and Citrus, found in Malaya. Gard. Bull. Straits Settlem. 5: 212–220.
• Mabberley, D. J. (1998). Australian Citreae with notes on other Aurantioideae (Rutaceae). Telopea 7 (4): 333-344. Available online (pdf).
• Fruits of warm climates
• Fortunella crassifolia Swingle - Fruits and Seeds Flavon's Wild herb and Alpine plants
• Fortunella at Wikispecies

See also

• Limequat [A cross between a Lime and a Kumquat]
• Orangequat [A cross between an Orange and a Kumquat]
• Calamondin [A cross between a Tangerine and a Kumquat]
• Loquat [Although Loquats are not related botanically to Kumquats, the two names come from the same Chinese word for "orange."]