| Koji orange | |
|---|---|
 | |
| Koji orange fruits | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Sapindales |
| Family: | Rutaceae |
| Genus: | Citrus |
| Species: | C. leiocarpa |
| Binomial name | |
| Citrus leiocarpa | |
| Forms | |
| |
| Synonyms | |
Koji orange (Citrus leiocarpa), also known as thesmooth-fruited orange, is aCitrus species native toJapan.[1] Thespecific epithet (leiocarpa) comes from theGreekλεῖοςleîos'smooth', andκαρπόςkarpós'fruit'. It is a taxonomical synonym ofCitrus aurantium.[2]
BesidesJapan, it is grown in theUnited States, and other parts ofEast Asia includingSouth Korea andChina.[2]
The fruit isoblate in shape, slightly ribbed, bright orange in color, very small, and very seedy, and for the latter two reasons it is not grown for commercial use. It ripens from October through November and has been cultivated since at least 1900. It may bemonoembryonic. The tree is densely branched and has a broad crown and a short, straight trunk. The leaves are dark green and elliptical in shape.[1]
Citrus leiocarpa is inferred to be a hybrid between a koji-type species (seed parent) and thetachibana orange (pollen parent,Citrus tachibana). Itsgenotype matches with that of thekomikan and toukan varieties.[3]
Citrus leiocarpa f.monoembryota, aform ofCitrus leiocarpa, was described byChozaburo Tanaka. Once believed to be a mutation of the koji orange, it has been revealed that it is a hybrid between koji (pollen parent) andkishu (seed parent).[3] In Chinese, it is called駿河柑子 (jun he gan zi) and is calledスルガユコウ (suruga yukō) and駿河柚柑 (suruga yuzukan) in Japanese.[4]
