Kumquat

Kumquats (or cumquats in Australian English, /ˈkʌmkwɒt/;^[2] Citrus japonica) are a group of small fruit-bearing trees in the flowering plant family Rutaceae. They were previously classified as forming the now historical genus Fortunella, or placed within Citrus sensu lato.

The edible fruit closely resembles the orange (Citrus sinensis) in color and shape but is much smaller, being approximately the size of a large olive. Kumquat is a fairly cold-hardy citrus.

Etymology[edit]

The English name "kumquat" derives from the Cantonese gām-gwāt 金橘, literally meaning "golden orange" or "golden tangerine".

Origin[edit]

The kumquat plant is native to south Asia and the Asia-Pacific region. The earliest historical reference to kumquats appears in literature of China from the 12th century. They have long been cultivated in India, Japan, Taiwan, the Philippines, and southeast Asia. They were introduced to Europe in 1846 by Robert Fortune, collector for the London Horticultural Society, and shortly thereafter were brought to North America.

Description[edit]

They are slow-growing evergreen shrubs or short trees that stand 2.5 to 4.5 meters (8 to 15 ft) tall, with dense branches, sometimes bearing small thorns. The leaves are dark glossy green, and the flowers are white, similar to other citrus flowers, and can be borne singly or clustered within the leaf-axils. Depending on size, the kumquat tree can produce hundreds or even thousands of fruits each year.^[3]

Varieties[edit]

Citrus taxonomy is complicated and controversial. Different systems place different types of kumquat in different species, or unite them in a single genus. Historically they were viewed as within the genus Citrus, but the Swingle system of citrus taxonomy elevated them to their own genus, Fortunella. Recent phylogenetic anlaysis suggests they indeed fall within Citrus.

Round kumquat[edit]

When the kumquats are divided into multiple species, the name Fortunella japonica (or Citrus japonica) is retained by the group. The round kumquat, also called Marumi kumquat or Morgani kumquat, is an evergreen tree that produces edible golden-yellow fruit. The round Hawaiian varietal, the "Meiwa kumquat", is typically eaten raw. The fruit is small and usually spherical but can be oval shaped. The peel has a sweet flavor, but the fruit has a distinctly sour center. The fruit can be eaten cooked but is mainly used to make marmalades, jellies, and other spreads. It is grown as an ornamental plant and can be used in bonsai cultivation. The plant symbolizes good luck in China and other Asian countries, where it is often kept as a houseplant and given as a gift during the Lunar New Year. Round kumquats are more commonly cultivated than other species due to their high cold tolerance.

Oval kumquat[edit]

When the kumquats are divided into multiple species, the name Fortunella margarita (or Citrus margarita) is used for this group. The oval kumquat is also called the Nagami kumquat.^[4] The most unusual feature of the Nagami kumquat is how the fruit is consumed; namely, that it is eaten whole, skin and all. The inside is still quite sour, but the skin has a very sweet flavour, so when eaten together an unusual tart-sweet, refreshing flavour is produced. The fruit ripens mid- to late winter and always crops very heavily, creating a spectacular display against the dark green foliage. The tree tends to be much smaller and dwarf in nature, making it ideal for pots and occasionally bonsai cultivation.

Jiangsu kumquat[edit]

When the kumquats are divided into multiple species, the name Fortunella obovata (or Citrus obovata) is used for this group. The Jiangsu kumquat or Fukushu kumquat bears edible fruit that can be eaten raw, as well as made into jelly and marmalade. The fruit can be round or bell shape and is bright orange when fully ripe. The plant can be distinguished from other kumquats by its distinctly round leaves. It is typically grown for its edible fruit and as an ornamental plant, but cannot withstand frost like the round kumquat. These kumquats are often seen near the Yuvraj section of the Nayak Province.

'Centennial Variegated' kumquat[edit]

The 'Centennial Variegated' kumquat cultivar arose spontaneously from the oval kumquat. It produces a greater proportion of fruit to peel than the oval kumquat, and the fruit are rounder and sometimes necked. Fruit are distinguishable by their variegation in color, exhibiting bright green and yellow stripes. The tree is distinguishable by its lack of thorns.^[5]

Cultivation and uses[edit]

Kumquats are much hardier than other citrus plants such as oranges. The Nagami kumquat requires a hot summer, ranging from 25 °C to 38 °C (77 °F to 100 °F), but can withstand frost down to about −10 °C (14 °F) without injury.

In cultivation in the UK, Citrus japonica has gained the Royal Horticultural Society’s Award of Garden Merit^[6] (confirmed 2017).^[7]

Propagation and pollination[edit]

Kumquats do not grow well from seeds and so are vegetatively propagated by using rootstock of another citrus fruit,^[8] air layering, or cuttings (using a rooting gel/powder).^[9] Like most citrus, they are self-pollinating.

Composition[edit]

The essential oil of the kumquat peel contains much of the aroma of the fruit, and is composed principally of limonene, which makes up around 93% of the total.^[10] Besides limonene and alpha-pinene (0.34%), both of which are considered monoterpenes, the oil is unusually rich (0.38% total) in sesquiterpenes such as α-bergamotene (0.021%), caryophyllene (0.18%), α-humulene (0.07%) and α-muurolene (0.06%), and these contribute to the spicy and woody flavor of the fruit. Carbonyl compounds make up much of the remainder, and these are responsible for much of the distinctive flavor. These compounds include esters such as isopropyl propanoate (1.8%) and terpinyl acetate (1.26%); ketones such as carvone (0.175%); and a range of aldehydes such as citronellal (0.6%) and 2-methylundecanal. Other oxygenated compounds include nerol (0.22%) and trans-linalool oxide (0.15%).^[10]

Hybrids[edit]

Hybrid forms of the kumquat include the following:

• Calamondin: mandarin orange x kumquat^[11]
• Citrangequat: citrange x kumquat
• Limequat: key lime x kumquat
• Orangequat: Satsuma mandarin x kumquat
• Procimequat: limequat x kumquat
• Sunquat: Meyer lemon (?) x kumquat
• Yuzuquat: yuzu x kumquat

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  Kumquat flower

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  Kumquat fruit cross-section

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  Kumquat whole and sectioned

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  Common kumquat

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  Round kumquats (or citrofortunella)

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  Round kumquats (or citrofortunella)

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  Koum Quat liqueurs from Corfu, Greece

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  Potted kumquat trees at a kumquat liqueur distillery in Corfu.

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  Slices of kumquat pie at the Kumquat Festival in Dade City, Florida

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  Bags of kumquat for sale at the Kumquat Festival

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  Kumquat Preserves

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  Flowers and fruit

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  Green fruit and leaves

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  Kumquat tree

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  Closeup from fruit in growth

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  Kumquats in growth

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  Ready to pick

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  Ripening

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  Kumquat or kumquat hybrid

See also[edit]

• Kumquat Festival

References[edit]

Further reading[edit]

• 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
• International Code of Botanical Nomenclature (Tokyo Code)

External links[edit]

Look up kumquat in Wiktionary, the free dictionary.

Wikimedia Commons has media related to Fortunella (Kumquat).

• Data related to Fortunella at Wikispecies
• Growing an Orange Tree in Hydroponic
• How to grow kumquats and other citrus from seed
• How to propagate by air layering.
• Kumquat Marmalade