Closely related trees typically have similar leaves, and sometimes they are very similar and hard to distinguish. Trees that are distantly related usually have noticeably different leaves. This is convenient and helpful for you when you try to identify a tree. Some trees produce leaves that don't all look alike, and the leaves on one particular kind of tree may seem to mimic those of another. Most of the trees with these leaves hold them throughout the winter season.
Needles are of varying lengths.
They grow either singly or in bundles. The stalk in turn is attached to a woody twig. When the stalk is removed from the twig a distinct scar is left on the twig. These multiple leaf blades are called leaflets. The leaflets that make up a single leaf are attached to a single stalk.