Trifoliate Orange, Poncirus trifoliata (syn. Citrus trifoliata), is a member of the family Rutaceae

Rutaceae

Rutaceae, commonly known as the rue or citrus family, is a family of flowering plants, usually placed in the order Sapindales.Species of the family generally have flowers that divide into four or five parts, usually with strong scents...

, closely related to Citrus

Citrus

Citrus is a common term and genus of flowering plants in the rue family, Rutaceae. Citrus is believed to have originated in the part of Southeast Asia bordered by Northeastern India, Myanmar and the Yunnan province of China...

, and sometimes included in that genus, being sufficiently closely related to allow it to be used as a rootstock

Rootstock

A rootstock is a plant, and sometimes just the stump, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The tree part being grafted onto the rootstock is usually called the scion...

 for Citrus. It differs from Citrus in having deciduous, compound leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

, and pubescent (downy) fruit.

It is native to northern China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 and Korea

Korea

Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...

, and is also known as the Chinese Bitter Orange.

The plant is fairly hardy (USDA zone 5) and will tolerate moderate frost and snow, making a large shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 or small tree

Tree

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

 4-8 m tall. Because of the relative hardiness of Poncirus, citrus grafted onto it are usually hardier than when grown on their own roots.

Description

Poncirus trifoliata is recognisable by the large 3-5 cm thorns on the shoots, and its deciduous leaves with three (or rarely, five) leaflets, typically with the middle leaflet 3-5 cm long, and the two side leaflets 2-3 cm long. The flowers are white, with pink stamens, 3-5 cm in diameter, larger than those of true citrus but otherwise closely resembling them, except that the scent is much less pronounced than with true citrus. As with true citrus, the leaves give off a spicy smell when crushed.

The fruits are green, ripening to yellow, and 3-4 cm in diameter, resembling a small orange

Orange (fruit)

An orange—specifically, the sweet orange—is the citrus Citrus × sinensis and its fruit. It is the most commonly grown tree fruit in the world....

, but with a finely downy surface. They are very bitter, are not edible fresh, but can be made into marmalade

Marmalade

Marmalade is a fruit preserve made from the juice and peel of citrus fruits, boiled with sugar and water. The benchmark citrus fruit for marmalade production in Britain is the "Seville orange" from Spain, Citrus aurantium var...

, and when dried and powdered, they can be used as a condiment

Condiment

A condiment is an edible substance, such as sauce or seasoning, added to food to impart a particular flavor, enhance its flavor, or in some cultures, to complement the dish. Many condiments are available packaged in single-serving sachets , like mustard or ketchup, particularly when supplied with...

.
Cultivation
The cultivar

Cultivar

A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...

 "Flying Dragon" is dwarfed in size and has highly twisted, contorted stems. It makes an excellent barrier hedge

Hedge

Hedge may refer to:* Hedge or hedgerow, line of closely spaced shrubs planted to act as a barrier* Hedge , investment made to limit loss* Hedge , intentionally non-committal or ambiguous sentence fragments-See also:...

 due to its density and thorns. Such a hedge had been grown for over 50 years at Oklahoma State University in Stillwater.

Traditional medicine

The fruits of Poncirus trifoliata are widely used in Oriental medicine as a remedy for allergic inflammation.

Potential pharmacology

In vitro

In vitro

In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

studies show that the fruits of Poncirus trifoliata might contribute to the treatment of mast cell

Mast cell

A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...

-derived allergic inflammatory diseases. The chemical compounds neohesperidin and poncirin

Poncirin

Poncirin is the 7-O-neohesperidoside of isosakuranetin. Poncirin can be extracted from trifoliate orange ....

 isolated from Poncirus trifoliata may be useful for the treatment of, and/or protection from, gastritis

Gastritis

Gastritis is an inflammation of the lining of the stomach, and has many possible causes. The main acute causes are excessive alcohol consumption or prolonged use of nonsteroidal anti-inflammatory drugs such as aspirin or ibuprofen. Sometimes gastritis develops after major surgery, traumatic...

. Poncirus trifoliata extracts have been shown to possess in vitro

In vitro

In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

anti-allergic, antitumor, anti-inflammatory and antiviral activities. Poncirus trifoliate extract could possess a wide range of beneficial activities for neurodegenerative disorders. A water extract, taken for 10 weeks, suppressed weight gain in rats.