The Norway maple is a species native to Scandinavian countries, Russia and much of Central Europe. It is a desirable shade tree, but when it "escapes" into nearby woodlands via its large number of seeds, its extensive shade can keep other plant species from thriving. Identify the Norway maple's leaves, which appear almost identical to those of a sugar maple, by concentrating on specific aspects of their makeup.

Opposite Leaves

Study the arrangements of the leaves on a tree to determine if it is a Norway maple. On all maples, the leaves grow in a pattern that botanists consider as "opposite." Look at a maple and you will observe that the buds, twigs and the leaves grow in pairs, with one opposite the other. On a twig the maple leaves develop in twos, with one emerging from one side of the twig and another leaf developing across from it on the other. A Norway maple is typical in this regard.

Shape

Look at the shape and size of a Norway maple leaf. While the sugar maple has a similarly shaped leaf in that it is palmate, or resembles an outstretched hand, the sugar maple leaf normally is longer that it is wide. The reverse is true for a Norway maple, with the average leaf about four to five inches long but as wide as six inches across. The leaf of the Norway maple will have between five and seven lobes, as does a sugar maple, but the various points on the edges of the leaf are more distinct on the Norway species.

Colors

Use the colors of Norway maple leaves to help identify them. They are dark green throughout the spring and summer, but they are most distinguishable as an identifier in the fall. Notice that the leaves stay on a Norway maple far longer than most other deciduous trees, in most cases not falling off the branches until November. They will not turn color until early November, finally going from green to yellow or gold before they ultimately drift away to the ground.

Other Traits

Make a positive identification a Norway maple by the white milky sap that flows from the stalk if you break it. Twist a stalk and you will notice a few drops of the sap coming out. Use tar spot as another feature to help you identify a Norway maple. A disease common to this tree, it gives the leaves brownish spots.

Source:

University of Connecticut: Norway Maple

"A Guide to Field Identification--Trees of North America"; C. Frank Brockman; 1986