Citrus aurantium, alias back to green orange, crustacean, lime flower. Evergreen shrubs, branches, slender, leaves alternate, leathery, oval, spring and summer (4-5) white flowers, rich aroma, fruit spheroidal, the winter is orange-red, the summer is turning green again, so Said: back to the green orange, because of the fruit of several generations of the same tree habit, also known as "Gongsun Orange."

Citrus aurantium is an evergreen shrub of the genus Rutaceae. The first year's fruit stays on the tree for winter, and the next year flowers and new fruit. The color of the fruit is yellow back to green, and the two generations of fruit are on the same tree. The flowers are slightly bitter, but the aroma is strong and the smell is forgetful. Flowers solitary or clustered in leaf axils; flowers dreamlike, apex 5-lobed, suborbicular, urate; petals usually 5-locate, oblong, white; The filament base is composed of several numbers: the ovary is superior, the spheroid is spherical, the style is cylindrical, and the stigma is head-shaped. The citrus fruit is orange-red (remaining on the tree until the next summer and turning to dirty green). It is nearly spherical, with a diameter of 7-8 cm. It has an enlarged dream of survival, and the sac is about 10 petals. Seeds are oval. Flowering in May, fruit ripening period in December.