What kind of leaf is this?

Question

This has become something of an argument with my friends and I,we regularly pass through this park and the grass is literally covered in these white leaves.And we've all said they're from a different tree,so can someone please settle this once and for all and tell me what tree produces these leaves?
I believe the leaves were a bright green with a silver underside but now they've fallen they've turned completely white on both sides.
http://img100.imageshack.us/my.php?image=leafdscn1886mp7.jpg

Answer 1

Populus alba White Poplar