Family: Aceraceae, Maple view all from this family

Description Introduced, invasive shade tree with rounded crown of dense foliage and with milky sap in leafstalks.
Height: 60' (18 m).
Diameter: 2' (0.6 m).
Leaves: opposite; 4-7" (10-18 cm) long and wide. Palmately 5-lobed; the shallow lobes and edges with scattered long teeth; 5 or 7 main veins from notched base. Dull green with sunken veins above, paler and hairless (except in vein angles) beneath; turning bright yellow in autumn. Long slender leafstalk, with milky sap at end when broken off.
Bark: gray or brown; becoming rough and furrowed into narrow ridges.
Twigs: brown, hairless.
Flowers: 5/16" (8 mm) wide; with 5 greenish-yellow petals; in upright or spreading clusters; usually male and female on separate trees; in early spring before leaves.
Fruit: 1 1/2-2" (4-5 cm) long; paired keys with long wing and flattened body; spreading widely, light brown, hanging on long stalk; maturing in summer.

Habitat A street tree, escaping along roadsides and into second-growth forest; in humid temperate regions.

Range Native across Europe from Norway to Caucasus and N. Turkey. Widely planted across the United States; naturalized in the Northeast south to North Carolina and west to Minnesota; also Washington and Idaho.

Discussion Norway Maple is fast-growing and tolerant of city smoke and dust, and thus has been a popular street tree. However, it escapes from cultivation and has begun invading forests, mainly in the Northeast, where it is considered one of the worst alien invasive plants. It outcompetes such native trees as Sugar Maple, shades out all understory growth, and changes the forest makeup. The species name, meaning "like Platanus," indicates the similarity of the leaves to those of Sycamore and Planetree, to which it is not related.