Citrus consists of root, stem, leaf, flower and fruit. Small arbor. It is a single compound leaf. The wing leaves are usually narrow or have only traces. The leaves are lanceolate, elliptic or wide oval, with large variation in size. There are usually notches at the top. The midvein forms forked branches from the base to the notch. At least the upper part of the leaf margin usually has blunt or rounded teeth, rarely entire.

Flowers solitary or 2-3 clustered; Calyx irregularly 5-3-lobed; Petals usually less than 1.5 cm long; Stamens 20-25, style slender, stigma capitate. The leaves of leaf citrus are evergreen single compound leaves, which are composed of leaf body and leaf wing. The wings are attached to the petioles.

Citrus species and varieties are different, with different sizes and shapes of leaves. The root is a group composed of taproot, lateral root, fibrous root and extremely short root hairs at the end of fibrous root, which is collectively called root system. Striped or propagated plants without taproot. The junction between trunk and root is called root neck. Branches Citrus branches are composed of trunk, main branch and lateral branch.

Fruit shaped species, usually oblate to nearly spherical, with thin and smooth peel, or thick and rough peel, light yellow, vermilion or dark red, very easy or slightly easy to peel, many or less orange, reticulate, easy to separate, usually soft, central column large and often empty, thin and full, ladyback 7-14 petals, thin or slightly thick wall, soft or quite tough, juice cells are usually spindle shaped, short and swollen, thin and long, pulp sour or sweet, or bitter, Or there is another special smell;

Seeds are either many or few, rarely seedless, usually ovoid, with narrow and sharp top, rounded base, dark green, light green or nearly milky white cotyledons, purple chalazal, polyembryonic, and few monoembryonic. The flowering period is from April to May, and the fruit period is from October to December.