Citron - Shitoron (English spelling) citron

It is an evergreen small to medium-sized tree of the Rutaceae family (APG classification: Rutaceae). It is also called Marbushukan. The leaves are oblong, and the flowers are terminal or axillary, with several flowers in a raceme. The petals are 4-5, white inside and pale purple outside, with one pistil and many stamens. In the subtropics and tropics, it blooms and bears fruit all year round. The fruit is spindle-shaped and weighs 150-200 grams. There is a papilla about 1.5 cm long at the apex. The melon sac (sac) is difficult to separate. The flesh is pale yellow and has a strong sour taste. It contains about 10 monoembryonic seeds. The fruit is boiled in sugar, and the juice is used as a beverage and as a source of citric acid. Fragrant oil is extracted from the peel and leaves, and it is dried for medicinal purposes. It is propagated by cuttings. It is said to have originated in the highlands upstream of the Ganges River, and was introduced to Italy from Persia in the 3rd to 2nd century BC. It was also recorded in China around 300 BC. In Japan, it was mentioned in the Honzo Zufu (1828). Bushcan (Buddha's hand) is a variety of citron with many separate stigmas and carpels, and the tip of the developing fruit is branched and palmate. The fruit weighs about 400 grams, and although the flesh does not develop well, it is often used as a bonsai.

[Muneo Iizuka October 16, 2020]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

ミカン科（APG分類：ミカン科）の常緑小木ないし中高木。マルブシュカンともいう。葉は長楕円(ちょうだえん)形、花は頂生または腋生(えきせい)で、数個が総状花序につく。花弁は4～5枚で、内部は白色、外側は淡紫色、雌しべは1本、雄しべは多数。亜熱帯や熱帯では周年開花結実する。果実は紡錘形で150～200グラム。果頂部に約1.5センチメートルの乳頭がある。瓤嚢(じょうのう)（袋）は分離しにくい。果肉は淡黄色で酸味が強い。約10粒の単胚(はい)性種子がある。果実は砂糖煮に、果汁は飲料とし、クエン酸の原料ともする。果皮や葉から香油をとるほか、乾燥して薬用とする。繁殖は挿木による。原産地はガンジス川上流の高地といわれ、紀元前3～前2世紀にはペルシアからイタリアに伝わった。中国でも前300年前後に記載がある。日本では『本草図譜』（1828）に記載されている。ブッシュカン（仏手柑）はシトロンの1変種で、柱頭と心皮が多数に分かれ、発育果の先端は分岐し掌状となる。果実は約400グラムで、果肉の発育はよくないが、よく盆栽にする。

［飯塚宗夫　2020年10月16日］

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