Citrus japonica Thunb.

Kum-quat (fr), kumquat (fr)

Species

Angiosperms > Sapindales > Rutaceae > Citrus

Characteristics

Trees to 5 m tall, d.b.h. to 20 cm. Branchlets numerous; spines variable, to 5 cm on young growth but some only a few mm on flowering shoots. Leaves 1-foliolate or sometimes mixed with simple leaves; petiole 6-9 mm, narrowly winged; leaf blade elliptic to obovate-elliptic, 4-6 × 1.5-3 cm, base rounded to broadly cuneate, margin dentate near apex or rarely entire, apex rounded and rarely mucronate. Flowers solitary or fascicled, subsessile. Calyx 4-or 5-lobed. Petals 5, ca. 5 mm or less. Stamens ca. 20; filaments cohering into 4 or 5 bundles. Ovary as long as style, 3-or 4-loculed, with 3 or 4 ovules per locule. Fruit bright orange to red, globose to slightly oblate, 9-10 mm in diam., smooth, 3-or 4-seeded; pericarp sweet and edible; sarcocarp acidic. Seeds broadly ovoid, apex mucronate; seed coat smooth; embryos at least sometimes numerous; cotyledons green. Fl. Apr-May, fr. Oct-Dec. 2n = 18*, 20*, 36*.
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An evergreen shrub up to 4 m high. It spreads to 2 m across. The stem is slender and branching. It has a rounded crown. It has spiny branches and shiny oval leaves with pointed tips. The leaves are leathery. Flowers are white with 5 petals. They occur singly and have a perfume. Fruit are very small and about 2.5 cm across. They are divided into only 3-6 sections. There are 2-5 seeds.
A shrub which keeps its leaves all year round. It grows about 2-4 m tall. It is spiny. The leaves are a narrow oval shape. They taper sharply at both ends. The leaf stalks have wings. The flowers are white, short and broad. The fruit are a flattened round shape. They are 1-2 cm across. They have 3-4 segments. The fruit become a bright orange when ripe.
A shrub or small tree. It often lacks thorns. The leaves are thick and rigid and often folded lengthwise. They have many dark green oil glands. The leaves are small. The leaf stalks have narrow wings. The fruit are oval or almost round. The fruit is small, orange and sweet. They are 3-4 cm across. The skin is edible. The fruit have about 7 segments.
A small evergreen tree. It is thorny. It grows to about 4 m high. The leaves are simple and entire. They are up to 7 cm long. They have blunt tips. They are leathery. The flowers are white. The fruit are 3 cm across. They are smooth and shiny. They are divided into 4-7 compartments. They are yellow. The skin is thin and waxy and is spicy.
Life form perennial
Growth form shrub
Growth support free-standing
Foliage retention evergreen
Sexuality hermaphrodite
Pollination entomogamy
Spread -
Mature width (meter) 1.5 - 2.5
Mature height (meter) 2.5 - 3.0
Root system -
Rooting depth (meter) 1.5
Root diameter (meter) -
Flower color
Blooming months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Fruit color
Fruiting months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Nitrogen fixer -
Photosynthetic pathway c3

Environment

It suits subtropical locations. It grows from sea level to at least 1150 m altitude in the tropics. It is cold tolerant. When dormant it can stand frosts, but not when in leaf. It cannot tolerate drought. It prefers well drained soils in an open sunny position. They cannot stand water-logging. They do best with a pH of 5 to 6. They cease growth when temperatures fall below 13°C. It suits hardiness zones 9-10.
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A tropical and subtropical plant. It grows in subtropical locations. In Nepal it grows between 1000-1500 m altitude. They can tolerate temperatures below freezing. They also show winter dormancy. It suits hardiness zones 9-10. Hobart Botanical Gardens.
It is widely grown in Chekiang province in China.
Evergreen broad-leaved forests; 600-1,000 metres.
It grows in subtropical locations.
Light 6-9
Soil humidity 3-7
Soil texture 2-5
Soil acidity 2-8
Soil nutriment -
Hardiness (USDA) 9-11

Usage

The ripe fruit can be eaten fresh, skin and all. (The seeds are removed) The fruit are often pickled or used in jam. They are preserved in syrup and pickled in vinegar. They are made into marmalade, sauces and jellies.
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The ripe fruit can be eaten whole or preserved. They are used for jams and jellies. (The seeds are removed)
The fruit are used for sweetmeats and candy. The fruit are preserved in honey and used as flavouring.
The fruit can be eaten raw. The skin can be eaten. The fruit can be preserved in sugar.
Uses environmental use essential oil food gene source material medicinal oil ornamental seasoning
Edible fruits seeds
Therapeutic use Parasympatholytics (bark), Pharyngitis (fruit), Mucusitis (unspecified), Parturition (unspecified), Sore(Throat) (unspecified)
Human toxicity -
Animal toxicity -

Cultivation

Plants are grown from seeds or by grafting. They can also be grown from cuttings. Seed need to be sown fresh. Plants can be trimmed as a hedge.
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Plants can be grown from seed.
Mode cuttings seedlings
Germination duration (days) -
Germination temperacture (C°) -
Germination luminosity -
Germination treatment -
Minimum temperature (C°) -6
Optimum temperature (C°) 26 - 35
Size -
Vigor -
Productivity -

Images

Flower

Citrus japonica flower picture by Nuong Nguyen (cc-by-sa)

Distribution

Citrus japonica world distribution map, present in Australia, Bolivia (Plurinational State of), Brazil, China, Cook Islands, Cuba, Dominican Republic, Fiji, Micronesia (Federated States of), Honduras, Haiti, India, Japan, Lao People's Democratic Republic, Sri Lanka, Mexico, Myanmar, Nepal, Pakistan, Palau, Korea (Democratic People's Republic of), Trinidad and Tobago, Taiwan, Province of China, United States of America, and Viet Nam

Identifiers

LSID urn:lsid:ipni.org:names:771939-1
WFO ID wfo-0000608080
COL ID VMKJ
BDTFX ID 18132
INPN ID 91806
Wikipedia (EN) Link
Wikipedia (FR) Link

Synonyms

Sclerostylis hindsii Citrus hindsii Citrus madurensis Fortunella bawangica Atalantia hindsii Citrus japonica Citrus margarita Fortunella crassifolia Fortunella hindsii Fortunella japonica Fortunella margarita Fortunella venosa Fortunella obovata Sclerostylis venosa Fortunella chintou Citrus microcarpa x Citrofortunella madurensis Citrus japonica var. madurensis Citrus japonica var. fructu-elliptica Fortunella hindsii var. chintou Citrus x var. globifera Citrus x var. japonica Citrus x subsp. japonica Citrus x var. olivicormis Citrus inermis Citrus japonica var. margarita Citrus nobilis var. microcarpa