Is this Bigleaf maple ?
I found this big leaf (12" across leaf) tree at my friend's house yard in Colorado. I think it is a maple but there is no winged fruits I see. Both sides of the leaves are shiny and smooth. All the books I have list the bigleaf maple (Acer macrophyllum) as having very deeply cut lobes. But this one is more like a sycamore leaf or Norway maple.
Could someone identify it for me?