Papeda or papaeda is the common name for a group of Citrus species and varieties native to tropical Asia that are hardy and slow-growing, and produce unpalatable fruit. Walter Tennyson Swingle segregated these species into a separate subgenus, Papeda, that included the Ichang lemon, yuzu, kaffir lime, kabosu, sudachi, and a number of wild and uncultivated species and hybrids. Recent genetic analysis shows the papedas to be distributed among distinct branches of the Citrus phylogenetic tree, and hence Swingle's proposed subgenus is polyphyletic and not a valid taxonomic grouping, but the term persists as a common name.[ citation needed ]
Because of generally slow growth and bitter, less palatable fruits than in other citruses, papeda species have only limited commercial cultivation. Some species, like ichang papeda, are used in landscaping, while others are important for rootstocking and as genome source for breeding disease-resistant and frost-hardy citrus hybrids. [1] In some cases the skin or leaves are used as a flavoring in Asian cuisine.[ citation needed ]
It is believed, based on molecular studies, that the citron, pomelo, mandarin and papedas were the ancestors of most hybrid citrus species and their varieties, which resulted from breeding or natural hybridization among the parental species. [2] For example, the Key lime, a hybrid between a papeda, the micrantha, and a citron, has in turn given rise to many commercial types of limes.[ citation needed ]
There are four species of Papeda currently recognised by Kew and the Missouri Botanical Garden. [3] These are:
There are many naturally occurring varieties that are now classified as subspecies:
A number of hybrids between this subgenus and the subgenus Citrus also exist:
Kumquats, or cumquats in Australian English, are a group of small, angiosperm, fruit-bearing trees in the family Rutaceae. Their taxonomy is disputed. They were previously classified as forming the now-historical genus Fortunella or placed within Citrus, sensu lato. 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 of the last two.
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.
A mandarin orange, 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 roughly spherical sweet orange. The taste is sweeter and stronger than the common orange. A ripe mandarin orange is firm to slightly soft, heavy for its size, and pebbly-skinned. The peel is thin and loose, with little white mesocarp, so they are usually easier to peel and to split into segments. Hybrids have these traits to lesser degrees. The mandarin orange is tender and is damaged easily by cold. It can be grown in tropical and subtropical areas.
Citrus cavaleriei, the Ichang papeda, is a slow-growing species of papeda that has characteristic lemon-scented foliage and flowers.
The tangerine is a type of citrus fruit that is orange in color, that is considered either a variety of Citrus reticulata, the mandarin orange, or a closely related species, under the name Citrus tangerina, or yet as a hybrid of mandarin orange varieties, with some pomelo contribution.
A lime is a citrus fruit, which is typically round, green in color, 3–6 centimetres (1.2–2.4 in) in diameter, and contains acidic juice vesicles.
The tangelo, Citrus × tangelo, is a citrus fruit hybrid of a Citrus reticulata variety, such as mandarin orange or tangerine, and a Citrus maxima variety, such as a pomelo or grapefruit. The name is a portmanteau of 'tangerine' and 'pomelo'.
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 Citrus unshiu without seeds made people prone to infertility. Citrus unshiu became popular in Japan after modernization started in the Meiji period. It was introduced to the West from the Satsuma region of Japan in 1878.
Yuzu is a citrus fruit and plant in the family Rutaceae of Chinese origin. Yuzu has been cultivated mainly in East Asia, though it has also recently been grown in New Zealand, Australia, Spain, Italy, and France.
Sudachi is a small, round, green citrus fruit of Japanese origin that is a specialty of Tokushima Prefecture in Japan. Harvested before it fully ripens to yellow, it is tart and not eaten as a table fruit but used to flavor sauces and marinades, desserts, and drinks in place of lemon or lime. Genetic analysis shows it to be the product of a cross between a yuzu and another citrus fruit akin to the koji and tachibana orange.
The Key lime or acid lime is a citrus hybrid native to tropical Southeast Asia. It has a spherical fruit, 2.5–5 centimetres in diameter. The Key lime is usually picked while it is still green, but it becomes yellow when ripe.
Sweet lemon and sweet lime refer to groups of citrus hybrids that contain low acid pulp and juice. They are hybrids often similar to non-sweet lemons or limes, but with less citron parentage. Sweet limes and lemons are not sharply separated:
The sweet lime, Citrus limettioides Tan., is often confused with the sweet lemon, C. limetta Tan., which, in certain areas, is referred to as "sweet lime". In some of the literature, it is impossible to tell which fruit is under discussion.
Citrus macroptera, natively known as hatkhora or cabuyao, Melanesian papeda, or wild orange, is a semi-wild species of citrus native to the Sylhet region of Bangladesh and the Barak Valley Division of the Indian state of Assam.
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 citron, mandarin orange, pomelo and papedas. The result of genetic crosses between kumquats and these other citrus would then be intergeneric hybrids, so a novel genus name was coined for them in 1975, by compounding the names of the contributing genera to form Citrofortunella. That the genus is of a hybrid nature is represented by a multiplication sign before the genus name, for example × Citrofortunella microcarpa. Recent phylogenetic work has shown kumquats to fall within Citrus rather than belonging to a distinct genus, meaning these would no longer be considered intergeneric hybrids, and use of Citrofortunella as a distinct genus name for these hybrids loses taxonomic validity. All would be placed instead within Citrus.
Citrus latipes, commonly called "Khasi papeda", is sometimes mistakenly identified as Kaffir lime. Native to Northeast India, the khasi papeda is a small, thorny tree that closely resembles both kaffir limes and ichang papedas. Though rarely eaten, and extremely rare in cultivation, the fruit is edible.
The micrantha is a wild citrus from the papeda group, native to southern Philippines, particularly islands of Cebu and Bohol. Two varieties are recognized: small-flowered papeda, locally known as biasong, and small-fruited papeda or samuyao.
The lumia is also called the pear lemon, since its shape resembles a pear. It is also called French lime and sometimes sweet lemon, even though it is not necessarily sweet.
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 rootstock are plants used as rootstock for citrus plants. A rootstock plant must be compatible for scion grafting, and resistant to common threats, such as drought, frost, and common citrus diseases.
Mandarin oranges are cultivated in many varieties. These include both the original wild mandarins and many hybrid varieties with other Citrus species.