I believe norway maple leaves have a white exudate that either weeps from the petiole or branch when the leaf is removed.

John

Theey have a green leaf bud, they produce there seed in the fall. Red and sugar produce in the spring. They have yellow fall.

Oh the silver maple also proudces in spring

Thanks so much for the replies. I think I may just have the one Norway maple. I will go out in the morning and check to see if the leaves or branches exude something white when a leaf is pulled off. Thanks again.
Jacquie

John is right about the white exudate being unique to Norway maples, but you usually have to wait until early summer for it to be apparent - too early now.

Another easy identification: The wings on the fruits(samaras)of Norway maples diverge from each other at a very wide angle. In other maples the angle is much more acute.

The bark is also distinctive on mature Norway maples: very dark gray broken into interlacing vertical furrows.

the easiest and SUREST way ... is to follow the link

and provide 3 pix..

leaf
trunk/bark
and the whole ...

none of this looking for weeping pus.. lol ...

ken

Here is a link that might be useful: how to post pix