SYCAMORE MAPLE (Ater pseudo-platanua). The most im portant hardwood of Europe, introduced into America as a shade tree; planted in avenues in Eastern cities; thrifty but short-lived. Distinguished by its thick, 5-lobed, crenate bordered leaves, of large size, and by the very long, pendulous racemes of flowers and keys, that hang all winter, giving the leafless trees an unkempt look.