Leaf shape very similar to sugar maple but more ornate. Milky sap when leaf is broken off of stem at the petiole . This sap is not found in sugar maple leaves and distinguishes the two species. Bark grayish, with vertical ridges and shallow furrows.
Flowers greenish yellow.
Fruits 2-winged, like all maples. Fruits September - October. On the trunks of many Norway maples, 'frost cracks' are apparent. The cracks occur on the south side of the trunk. The bark is warmed by the sun and then contracts in sudden temperature drops such as frosts, cracking in the process.