Yuzu (Citrus junos, from Japanese or ) is a citrus fruit and plant in the family Rutaceae of East Asian origin. Yuzu has been cultivated mainly in East Asia, though recently also in New Zealand, Australia, Spain, Italy, and France. It is believed to have originated in central China as an F1 hybrid of the mangshanyeju subspecies of mandarin orange and the ichang papeda. Description This fruit resembles a small grapefruit with uneven skin and can be either yellow or green depending on the degree of ripeness. Yuzu fruits, which are very aromatic, typically range between in diameter but can be as large as a regular grapefruit (up to , or larger). Yuzu forms an upright shrub or small tree, which commonly has many large thorns. Leaves are notable for a large, leaf-like petiole, resembling those of the related makrut lime and ichang papeda, and are heavily scented. Yuzu closely resembles sudachi (Citrus sudachi, a Japanese citrus from Tokushima Prefecture, a yuzu–mandarin orange cross) in many regards, though, unlike the sudachi, yuzu eventually ripen to an orange colour and there are subtle differences between the flavors of the fruit. Cultivation The yuzu originated and grew wild in central China and Tibet region. It was introduced to Japan and Korea during the Tang dynasty and is still cultivated there. It grows slowly, generally requiring ten years to fruit. To shorten the duration to fruiting, it may be grafted onto karatachi (P. trifoliata). It is unusual among citrus plants in being relatively frost-hardy, due to its cold-hardy Ichang papeda ancestry, and can be grown in regions with winters as low as where more sensitive citrus would not thrive. Varieties and similar fruits In Japan, an ornamental version of yuzu called "flower yuzu" is also grown for its flowers rather than its fruit. A sweet variety of yuzu known as the yuko, only present in Japan, became severely endangered during the 1970s and 1980s; a major attempt has been made to revive this varietal in southern Japan. Another variety of yuzu in Japan, with knobby skin, is called . Dangyuja, a Korean citrus fruit from Jeju Island, is often considered a type of yuzu due to its similar shape and flavor, but it is genetically a variety of pomelo. Use East Asia Culinary use Japan Yuzu's domestic production is about 27,000 tons (2016). Though rarely eaten as a fruit, yuzu is a common