Leaves: large, not pointed like Norway maple (below) with long stalks of up to 20cm.
wedge-shaped separation (cf rounded separations of Norway maple)
Winged fruits Sept and Oct. set at an angle of approx 90 deg. (cf 160 deg for the Norway maple)
Leaves are maple- and sycamore-like but have sharp points with curved bends in between:
Spiky spherical fruits hang down instead of winged fruits.
Knobbly trunk. Its bark absorbs pollution then is shed
Leaves arranged in pairs and their lobes are more rounded than those of the sycamore (as shown below in photograph):
(see Simple leaves: lobed for more details)