Citrus unshiu is a seedless and easy-peeling citrus species, also known as unshu mikan, cold hardy mandarin, satsuma mandarin, satsuma orange, Christmas orange, and tangerine. It is of Chinese origin and introduced elsewhere.
In China, it is known as Wenzhou migan (Chinese: 温州蜜柑; pinyin: Wēnzhōu Mìgān); In Japan, it is known as mikan or formally unshu mikan (温州蜜柑 unshū mikan?), the result of the local reading of the same characters used in Chinese. In both languages, the name means "Honey Citrus of Wenzhou", Wenzhou being a city in Zhejiang province, China. It is also often known as "Seedless mandarin" (Chinese: 无核桔; pinyin: wúhé jú).
The Afrikaans name naartjie is also used in South African English. It derives originally from the Tamil word nartei meaning citrus. The word has been used in South Africa since 1790, but the first written recorded English use is by Lawrence Green in the Tavern of the Seas, 1947.
Its fruit is "one of the sweetest citrus varieties, with a meltingly tender texture" and usually seedless, about the size of other mandarin oranges (Citrus reticulata). One of the distinguishing features of the satsuma is the thin, leathery skin dotted with large and prominent oil glands, which is lightly attached around the fruit, enabling it to be peeled very easily in comparison to other citrus fruits. The satsuma also has particularly delicate flesh, which cannot withstand the effects of careless handling. The uniquely loose skin of the satsuma, however, means that any such bruising and damage to the fruit may not be immediately apparent upon the typical cursory visual inspection associated with assessing the quality of other fruits. In this regard, the satsuma might be categorised as a hit-and-miss citrus fruit; the loose skin particular to the fruit precluding the definitive measurement of its quality by sight and feel alone.
Satsumas grown in humid areas may be ripe while the skin is still green.
The Chinese and Japanese names reference Wenzhou, a city in the Zhejiang Province of China known for its citrus production. In 1916, a number of Japanese cultivars were introduced to Wenzhou. These, and new cultivars developed from them, now dominate orchards in Wenzhou. The traditional centre of satsuma production in Wenzhou is in the town of Wushan, in the Ouhai District of Wenzhou.. However, the satsuma originates from Japan, where it is known as the unshu mikan, and from whence it was introduced to Florida in 1878. The satsuma's nickname of "Christmas orange" comes from its history as a Christmas treat in Britain.
Export to the West
Jesuits brought the fruit from Asia to New Spain. Groves were started by Jesuits in the 18th century in the Jesuit Plantation upriver from New Orleans. The Municipal Street "Orange" in New Orleans, was originally named "Rue Des Orangers" and the site of the Jesuit grove. The groves were later re-cultivated farther south in Plaquemines Parish, Louisiana to provide greater protection from harmful frosts, and have continued to the present day. The Becnel family are the largest growers of Louisiana Citrus.
The fruit became much more common in the United States starting in the late 19th century. In 1876 during the Meiji period, Owari mikans were brought to the United States from the Satsuma Province in Kyūshū, Japan, by a spouse of a member of the U.S. Embassy, who renamed them satsumas. While the species originates from Japan, it does not originate from the Satsuma Province in particular. Between 1908 and 1911 about a million Owari mikan trees were imported. Owari is still commonly grown in Florida. The towns of Satsuma, Alabama; Satsuma, Florida; Satsuma, Texas; and Satsuma, Louisiana were named after this fruit. By 1920 Jackson County in the Florida Panhandle had billed itself as the "Satsuma Capital of the World." However, the commercial industry was damaged by a -13 °C cold snap in 1911, a hurricane in 1915, and a very cold period in the late 1930s. Satsumas are cold-hardy, and when planted in colder locations, the fruit becomes sweeter from the colder temperatures. A mature satsuma tree can survive down to –9.5 °C (15 °F) or even -11 °C for a few hours. Of the edible citrus varieties, only the kumquat is more cold-hardy. Satsumas rarely have any thorns, an attribute that also makes them popular. They can be grown from seed, which takes about 8 years until the first fruits are produced, or grafted onto other citrus rootstocks, trifoliate orange being one of the most popular.
Possibly not hybrids
- Amanatsu (pumello hybrid)
- Kinkoji unshiu (C. obovoidea(kinkoji) × C. unshiu) 
- Dekopon is a kiyomi hybrid
- Kobayashi mikan (C. natsudaidai × C.unshiu)
- ? Natsudaidai (pomelo × mikan)
- Shonan Gold
- "Japanese Mikan and Satsuma Oranges". hawaii.edu.
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(natural distribution) Japan
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- "Plant Name Details: Rutaceae Citrus unshiu Marcow.". International Plant Names Index.
Original Data: Notes: Japon
- "Taxon: Citrus unshiu Marcow.". Germplasm Resources Information Network(GRIN), United States Department of Agriculture.
probable origin Japan
- Misaki, Akira (November 1999). "紀州有田みかんの起源と発達史(The Origin and the Development-Process of "Kisyu Arida Mikan(Arida Mandarin)")". 経済理論(The Wakayama Economic Review) (in Japanese) (University of Wakayama) 292: 97–118.
(After the many years of research, Dr. Tanaka has concluded the place of origin of Satsuma is Nagashima, Kagoshima. Satsuma is a chance seedling of Sōkitsu, Mankitsu, or Tendaisankitsu introduced from Huangyan Zhejiang, China. It appeared in the early Edo period.)Archived by Arita Mikan Database at http://www.mikan.gr.jp/report/kigen/index.html
- Branford, Jean (1978). A dictionary of South African English. Oxford.
- "Assessing genetic diversity and population structure in a citrus germplasm collection utilizing simple sequence repeat markers (SSRs)". doi.org.
- Elisa Bosley. "In Season: Satsuma Oranges". CookingLight. Retrieved 2015-02-25.
- P. C. Andersen, J. J. Ferguson, and T. M. Spann. "HS195/CH116: The Satsuma Mandarin". ufl.edu.
- "WWNO: Satsumas (2009-10-03)". Publicbroadcasting.net. 2009-10-03. Retrieved 2009-12-06.
- "kinkoji_unshiu". ucr.edu.
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