Japanese name: ユズ（柚子、柚） Scientific name:Citrus junos
An evergreen tree native to the upper Yangtze River in China, the most cold-hardy of the genus Citrus.
It is semi-arborescent and somewhat upright.
The branches have sharp thorns.
The alternate leaves look simple, but they are reduced compound leaves; they are entire, leathery, and have broad winged petioles.
The flowers are white slightly tinged with purple and fragrant.
Many stamens are fused up to the middle of the filaments, forming a staminal tube.
The fruit is oblate, about 100–130 g, with an uneven surface, and ripens yellow.
The peel is rather thick with a distinctive strong scent and is used as a condiment and the like.
The juice is strongly acidic and is used as vinegar and as a raw material for processed products.
It is said to have come to Japan in the Nara or Asuka period.
It is highly valued for ceremonial use, such as being added to the winter solstice bath as a medicinal bath and used in New Year gate decorations.
It is a food plant of the swallowtail butterfly.
