Koji orange
species of plant
Koji orange (Citrus leiocarpa), also known as the smooth-fruited orange, is a Citrus species native to Japan. The specific epithet (leiocarpa) comes from the Greek λεῖος leîos 'smooth', and καρπός karpós 'fruit'. It is a taxonomical synonym of Citrus aurantium.
Distribution
Besides Japan, it is grown in the United States, and other parts of East Asia including South Korea and China.
Description
The fruit is oblate 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 be monoembryonic. The tree is densely branched and has a broad crown and a short, straight trunk. The leaves are dark green and elliptical in shape.
Genetics
Citrus leiocarpa is inferred to be a hybrid between a koji-type species (seed parent) and the tachibana orange (pollen parent, Citrus tachibana).
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Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated Sep 28, 2025. The linked authority identifier is Q10349285. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1900.
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This entry incorporates text from “Koji orange” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.