Kumquats ( ), or cumquats in

Australian English Australian English (AusE, AusEng, AuE, AuEng, en-AU) is the set of variety (linguistics), varieties of the English language native to Australia. It is the country's common language and ''de facto'' national language. While Australia has no of ...

, are a group of small,

angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit ...

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

-bearing

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

s in the family

Rutaceae The Rutaceae () is a family (biology), family, commonly known as the rueRUTACEAE
in Bo ...

. Their

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

is disputed. They were previously classified as forming the now-historical genus ''Fortunella'' or placed within ''

Citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

'', . Different classifications have alternatively assigned them to anywhere from a single species, '' Citrus japonica'', to numerous species representing each cultivar. Recent genomic analysis defines three pure species, '' Citrus hindsii'', '' C. margarita'' and '' C. crassifolia'', with ''C.'' × ''japonica'' being a

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

of the last two. The edible fruit closely resembles the

orange Orange most often refers to: *Orange (fruit), the fruit of the tree species '' Citrus'' × ''sinensis'' ** Orange blossom, its fragrant flower ** Orange juice *Orange (colour), the color of an orange fruit, occurs between red and yellow in the vi ...

(''Citrus x sinensis'') in color, texture, and anatomy, but is much smaller, being approximately the size of a large

olive The olive, botanical name ''Olea europaea'' ("European olive"), is a species of Subtropics, subtropical evergreen tree in the Family (biology), family Oleaceae. Originating in Anatolia, Asia Minor, it is abundant throughout the Mediterranean ...

. The kumquat is a fairly

cold-hardy citrus Cold-hardy citrus is citrus with increased frost tolerance and which may be cultivated far beyond traditional citrus growing regions. Citrus species and citrus hybrids typically described as cold-hardy generally display an ability to withstand wi ...

Etymology

The English word ''kumquat'' is a borrowing of the

Cantonese Cantonese is the traditional prestige variety of Yue Chinese, a Sinitic language belonging to the Sino-Tibetan language family. It originated in the city of Guangzhou (formerly known as Canton) and its surrounding Pearl River Delta. While th ...

(; zh, c=金橘), from "golden" + "orange".

Description

Kumquat plants have thornless branches and extremely glossy

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

. They bear dainty white flowers that occur in clusters or individually inside the leaf axils. The plants can reach a height from , with dense branches, sometimes bearing small thorns. They bear yellowish-orange fruits that are oval or round in shape. The fruits can be in diameter and have a sweet, pulpy skin and slightly acidic inner pulp. The fruit is often eaten whole by humans and has a taste which is sweet and somewhat sour. Kumquat trees are

self-pollinating Self-pollination is a form of pollination in which pollen arrives at the Stigma (botany), stigma of a flower (in flowering plants) or at the ovule (in gymnosperms) of the same plant. The term cross-pollination is used for the opposite case, where ...

Species

Citrus taxonomy Citrus taxonomy is the botanical classification of the species, varieties, cultivars, and graft hybrids within the genus ''Citrus'' and related genera, found in cultivation and in the wild. Citrus taxonomy is complex and controversial. Cultiva ...

is complicated and controversial. Different systems place various types of kumquats in different species or unite them into as few as two species. Botanically, many of the varieties of kumquats are classified as their own species, rather than a cultivar. Historically they were viewed as falling within the genus ''Citrus'', but the Swingle system of citrus taxonomy elevated them to their own genus, ''Fortunella''. Recent phylogenetic analysis suggests they do fall within ''Citrus''. Swingle divided the kumquats into two subgenera, the ''Protocitrus'', containing the primitive Hong Kong kumquat, and ''Eufortunella'', comprising the round, oval kumquat, Meiwa kumquats, to which Tanaka added two others, the Malayan kumquat and the Jiangsu kumquat. Chromosomal analysis suggested that Swingle's ''Eufortunella'' represent a single 'true' species, while Tanaka's additional species were revealed to be likely hybrids of ''Fortunella'' with other ''Citrus'', so-called x''

Citrofortunella 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 ...

''. One recent genomic analysis concluded there was only one true species of kumquat, but the analysis did not include the Hong Kong variety seen as a distinct species in all earlier analyses. A 2020 review concluded that genomic data were insufficient to reach a definitive conclusion on which kumquat cultivars represented distinct species. In 2022, a genome-level analysis of cultivated and wild varieties drew several conclusions. The authors found support for the division of kumquats into subgenera: ''Protocitrus'', for the wild Hong Kong variety, and ''Eufortunella'' for the cultivated varieties, with a divergence predating the end of the

Quaternary glaciation The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial period, glacial and interglacial, interglacial periods during the Quaternary period that began 2.58 Year#SI prefix multipliers, Ma (million ...

, perhaps between two ancestral populations isolated south and north, respectively, of the Nanling mountain range. Within the latter group, the oval, round and Meiwa kumquat each showed a level of divergence greater than between other recognized citrus species, such as between pomelo and citron, and hence each merits species-level classification. Though Swingle had speculated that the Meiwa kumquat was a hybrid of oval and round kumquats, the genomic analysis suggested instead that the round kumquat was an oval/Meiwa hybrid.

Hybrids

Hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

forms of the kumquat include the following: *

Calamansi Calamansi (''Citrus'' × ''microcarpa''), also known as calamondin, Philippine lime, or Philippine lemon, is a citrus hybrid cultivated predominantly in the Philippines. It is native to the Philippines, parts of Indonesia (Borneo, Sumatra, and ...

mandarin orange A mandarin orange (''Citrus reticulata''), often simply called mandarin, is a small, rounded citrus tree fruit. Treated as a distinct species of orange, it is usually eaten plain or in fruit salads. The mandarin is small and oblate, unlike the ...

x kumquat * Citrangequat:

citrange The citrange (a portmanteau of ''citrus'' and ''orange'') is a citrus hybrid of the sweet orange and the trifoliate orange. The purpose of this cross was to attempt to create a cold hardy citrus tree (which is the nature of a trifoliate), wi ...

x kumquat *

Limequat The limequat (''Citrus'' × ''floridana'') is a citrus hybrid that is the result of a cross between the Key lime and the kumquat, hybridized by Walter Tennyson Swingle in 1909. Description It is a small tree that grows into a contained bu ...

key lime The Key lime or acid lime (''Citrus'' × ''aurantiifolia'' or ''C. aurantifolia'') is a citrus hybrid (''kaffir lime, C. hystrix'' × ''citron, C. medica'') native to tropical Southeast Asia. It has a spherical fruit, in diameter. The Key lime ...

x kumquat *

Orangequat The mandarinquat, also misleadingly called orangequat, is any cross between a mandarin and a kumquat ('' Citrus crassifolia''). Mandarinquats are members of the citrofortunella group. The variety Nippon orangequat was first introduced in 1932 b ...

Satsuma mandarin ''Citrus unshiu'' is a semi-seedless and easy-peeling citrus species, also known as the satsuma mandarin or Japanese mandarin. During the Edo period of Japan, kishu mikans were more popular because there was a popular superstition that eating '' ...

x kumquat *

Procimequat Procimequat is a triploid citrus hybrid or transgeneric hybrid, ('' Citrus aurantifolia'' 'Mexican' x '' Fortunella japonica'') x '' Fortunella hindsii'', in which the limequat that itself is a cross between lime and a round kumquat, was backc ...

limequat The limequat (''Citrus'' × ''floridana'') is a citrus hybrid that is the result of a cross between the Key lime and the kumquat, hybridized by Walter Tennyson Swingle in 1909. Description It is a small tree that grows into a contained bu ...

x kumquat *

Sunquat A sunquat, also known as lemonquat or lemondrop, is a variety of citrus fruit, having an edible rind. It was initially created by Leslie Cude in Beeville, Texas, as a chance hybrid between a lemon (likely a 'Meyer') and a kumquat Kumquats ...

Meyer lemon ''Citrus'' × ''meyeri'', the Meyer lemon (), is a hybrid citrus fruit native to China. It is a cross between a citron and a mandarin/pomelo hybrid. Mature trees are around tall with dark green shiny leaves. The flowers are white with a purp ...

(?) x kumquat *

Yuzuquat A ''yuzuquat'' is a trigeneric hybrid between a Yuzu lemon (''Citrus ichangensis'' x ''C. reticulata'') and 'Nagami' kumquat (''C. japonica'' 'Nagami'). It was developed by John Brown in Texas. The fruit often is used as a lemon The lem ...

yuzu Yuzu (''Citrus'' × ''junos'', from Japanese language, Japanese or ; ) is a citrus fruit and plant in the family Rutaceae of China, Chinese origin. Yuzu has been cultivated mainly in East Asia, though it has also recently been grown in New Z ...

x kumquat

Origin and distribution

The kumquat plant is native to Southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. The historical reference to kumquats appears in literature of China from at least the 12th century. They have been cultivated for centuries in other parts of East Asia, South Asia, and Southeast Asia. They were introduced into

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

in 1846 by

Robert Fortune Robert Fortune (16 September 1812 – 13 April 1880) was a Scottish botanist, plant hunter and traveller, best known for introducing around 250 new ornamental plants, mainly from China, but also Japan, into the gardens of Britain, Australia, an ...

, collector for the

London Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nor ...

, and are now found across the world.

Cultivation

Kumquats are much hardier than citrus plants such as

oranges The orange, also called sweet orange to distinguish it from the bitter orange (''Citrus × aurantium''), is the fruit of a tree in the family Rutaceae. Botanically, this is the hybrid ''Citrus'' × ''sinensis'', between the pomelo (''Citrus m ...

. Sowing seed in the spring is most ideal because the temperature is pleasant with more chances of rain and sunshine. This also gives the tree enough time to become well established before winter. Early spring is the best time to transplant a sapling. They do best in direct sunlight (needing 6–7 hours a day) and planted directly in the ground. Kumquats do well in USDA hardy zones 9 and 10 and can survive in temperatures as low as . On trees mature enough, kumquats will form in about 90 days. In cultivation in the UK, ''Citrus japonica'' has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

(confirmed 2017).

Propagation

Kumquats do not grow well from seeds and so are vegetatively propagated by using

rootstock A rootstock is part of a plant, often an underground part, from which new above-ground growth can be produced. It could also be described as a stem with a well developed root system, to which a bud from another plant is grafted. It can refer to ...

of another citrus fruit,

air layering Layering is a vegetative propagation technique where the stem or branch of a plant is manipulated to promote root development while still attached to the parent plant. Once roots are established, the new plant can be detached from the parent an ...

, or cuttings.

Varieties

The ''Nordmann seedless'' is a seedless cultivar of the Nagami kumquat (''

Citrus margarita ''Citrus margarita'', the oval kumquat or Nagami kumquat, is a species of kumquat; a type of citrus fruit in the genus ''Citrus'', family Rutaceae. Its epithet, margarita, is Latin for pearly. It is first described by the Portuguese botanist Joã ...

''). It is similar to Nagami but with a slightly different shape and lighter skin. The C''entennial Variegated'' is another cultivar of the Nagami kumquat. It originated from the open pollination of a Nagami kumquat tree. The fruits are striped light green and yellow when underripe, and turn orange and lose their stripes when they ripen. They are oval-shaped, necked, 2.5 inches long and have a smooth rind. They mature in winter. This

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

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, and by its lack of thorns. The ''Puchimaru kumquat'' is a seedless or virtually seedless Japanese kumquat cultivar. It is resistant to citrus canker and citrus scab. The fruit weighs 11–20 grams and is ellipsoid in shape. It has a dark orange rind which is 4 millimeters thick. The juice content is relatively low. The oil glands are somewhat large and conspicuous. It ripens in January.

Uses

Nutrition

A raw kumquat is 81% water, 16%

carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...

s, 2%

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

, and 1%

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

(table). In a reference amount of , raw kumquat supplies of

food energy Food energy is chemical energy that animals and humans derive from food to sustain their metabolism and muscular activity. Most animals derive most of their energy from aerobic respiration, namely combining the carbohydrates, fats, and protein ...

and is a rich source of

vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription di ...

(49% of the

Daily Value In the U.S. and Canada, the Reference Daily Intake (RDI) is used in nutrition labeling on food and dietary supplement products to indicate the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97� ...

), with no other

micronutrient Micronutrients are essential chemicals required by organisms in small quantities to perform various biogeochemical processes and regulate physiological functions of cells and organs. By enabling these processes, micronutrients support the heal ...

s in significant content (table).

Essential oil

The

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the ...

of the kumquat peel contains much of the aroma of the fruit, and is composed principally of

limonene Limonene () is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the essential oil of citrus fruit peels. The (+)-isomer, occurring more commonly in nature as the fragrance of oranges, ...

, which makes up around 93% of the total. Besides limonene and alpha-pinene (0.34%), both of which are considered

monoterpene Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen func ...

s, the oil is unusually rich (0.38% total) in

sesquiterpene Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many combinations. Biochemical modifications s ...

s such as α-

bergamotene Bergamotenes are a group of isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in s ...

(0.021%),

caryophyllene Caryophyllene (), more formally (−)-β-caryophyllene (BCP), is a natural bicyclic sesquiterpene that occurs widely in nature. Caryophyllene is notable for having a cyclobutane ring, as well as a ''trans''-double bond in a 9-membered ring, both ...

(0.18%), α-

humulene Humulene, also known as α-humulene or α-caryophyllene, is a naturally occurring monocyclic sesquiterpene (C15H24), containing an 11-membered ring and consisting of 3 isoprene units containing three nonconjugated C=C double bonds, two of them b ...

(0.07%) and α-muurolene (0.06%), and these contribute to the spicy and woody flavor of the fruit.

Carbonyl In organic chemistry, a carbonyl group is a functional group with the formula , composed of a carbon atom double bond, double-bonded to an oxygen atom, and it is divalent at the C atom. It is common to several classes of organic compounds (such a ...

compounds make up much of the remainder, and these are responsible for much of the distinctive flavor. These compounds include

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

s such as isopropyl propanoate (1.8%) and terpinyl acetate (1.26%);

ketone In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone ( ...

s such as

carvone Carvone is a member of a family of chemicals called terpenoids. Carvone is found naturally in many essential oils, but is most abundant in the oils from seeds of caraway (''Carum carvi''), spearmint (''Mentha spicata''), and dill. Uses Food appli ...

(0.175%); and a range of

aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...

s such as

citronellal Citronellal or rhodinal ( C10 H18 O) is a monoterpenoid aldehyde, the main component in the mixture of terpenoid chemical compounds that give citronella oil its distinctive lemon scent. Citronellal is a main isolate in distilled oils from the ...

(0.6%) and

2-methylundecanal 2-Methylundecanal is an organic compound that is found naturally in kumquat peel oil. This compound smells herbaceous, orange, and ambergris-like. At high dilution it has a flavor similar to honey and nuts. It is a colorless or pale yellow liquid ...

. Other oxygenated compounds include

nerol Nerol is a monoterpenoid alcohol found in many essential oils such as lemongrass and hops. It was originally isolated from neroli oil, hence its name. This colourless liquid is used in perfumery. Like geraniol, nerol has a sweet rose odor but it ...

(0.22%) and ''trans''-linalool oxide (0.15%).

Gallery

File:Hoa quất.jpg, Kumquat flower File:Quinotos.jpg, Kumquat fruit cross-section File:Kumquat.jpg, Kumquat whole and sectioned File:Citrus japonica1.jpg, Round kumquats (or

citrofortunella 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 ...

) File:Starr 070111-3157 Fortunella sp..jpg, Round kumquats (or

) File:KoumQuatLiqueur.jpg, Kumquat

liqueur A liqueur ( , ; ) is an alcoholic drink composed of Liquor, spirits (often rectified spirit) and additional flavorings such as sugar, fruits, herbs, and spices. Often served with or after dessert, they are typically heavily sweetened and un-age ...

s from

Corfu Corfu ( , ) or Kerkyra (, ) is a Greece, Greek island in the Ionian Sea, of the Ionian Islands; including its Greek islands, small satellite islands, it forms the margin of Greece's northwestern frontier. The island is part of the Corfu (regio ...

, Greece File:Kumquat Trees (Corfu).JPG, Potted kumquat trees at a kumquat liqueur distillery in

. File:Kumquat pie.JPG, Slices of kumquat pie at the

Kumquat Festival The Kumquat Festival is an annual celebration held each January in downtown Dade City, Florida focused on the kumquat—a small, tart citrus fruit traditionally consumed whole, including its sweet, edible peel. Organized by the East Pasco Chambe ...

Dade City Dade City, officially the City of Dade City, is a city in, and the county seat of Pasco County, Florida, United States. It is located in the Tampa Bay Area, northeast of Tampa and southwest of Orlando. The population was 7,275 as of the 2020 c ...

, Florida File:Kumquat jelly and kumquat butter.JPG, Kumquat

preserves Fruit preserves are preparations of fruits whose main preserving agent is sugar and sometimes acid, often stored in glass jars and used as a condiment or spread. There are many varieties of fruit preserves globally, distinguished by the meth ...

File:Fortunella (kumquat) 9 fiore+frutto.JPG, Flowers and fruit File:Citrus japonica3.jpg, Kumquat tree File:Muntala.jpg, alt=Unripe Kumquat, Unripe kumquat File:Fortunella japonica Frutigen.jpg, Ripened kumquat File:CDC kumquat3.jpg, Kumquat

References

External links

* * * {{Authority control Citrus Flora of temperate Asia Flora of tropical Asia Fruits originating in East Asia Garden plants of Asia Ornamental trees * Fruit trees Plant common names

Etymology

Description

Species

Hybrids

Origin and distribution

Cultivation

Propagation

Varieties

Uses

Nutrition

Essential oil

Gallery

See also

References

Further reading

External links