Amur maple

I saw a tree with opposite, lobed leaves.  Probably some kind of maple? The name that popped into my head was amur maple.  When I got home, I checked my books.  Yes, amur maple was the maple that most resembled the tree I saw.  I hadn't even known that amur maple was a tree I know.  That has happened before.  That's the way I like to learn trees -- I look at pretty pictures in the book, and they sneak into my brain without my knowing it.