Not generally considered a native, probably having been introduceD (from China ?) in medieval times. But see . Sycamore grows well in Ireland, profusely even, seeds germinate readily, and as a consequence it is extremely common in woodland, hedgerows and ditches, field boundaries, gardens, even growing through paving, in yards, and on old and neglected buildings.
Pollen grains are distinctive rounded heptangular or less usually quadrangular. When fresh the internal cytoplasm forms distinct arcs between adjacent pores. Five, or four, large and clear pores, one on each apex of the grain. About 25-30 microns across.