Leaves are alternate, simple, with thorns or spines present.
The leaves are 3 to 5 inches long 
and do not have teeth along the margin. They are thick, firm, and dark
greenin color. The buds are partly hidden in the bark and the terminal
bud is absent. The twigs have thorns that are straight and 1/2
inch in length.
The fruit is round, wrinkled, pale green in
color and 4 to 5 inches in diameter. It consists of numerous small seeds
crowded and grown together to form the characteristic "orange." When crushed,
the pulpy fruit gives a bitter, milky 
juice.
The bark on young twigs is green. On older trunks it is orange-brown
and deeply furrowed. The inner bark is bright orange. The bark of the roots
is also a bright orange color and furnishes a yellow dye.
[Tree Identification Homepage] - [ISUForestry Extension] - [ISU Extension]