the london plane is a large deciduous tree growing , exceptionally over tall, with a trunk up to or more in circumference. the bark is usually pale grey-green, smooth and exfoliating, or buff-brown and not exfoliating. the leaves are thick and stiff-textured, broad, palmately lobed, superficially maple-like, the leaf blade long and broad, with a petiole long. the young leaves in spring are coated with minute, fine, stiff hairs at first, but these wear off and by late summer the leaves are hairless or nearly so. the flowers are borne in one to three (most often two) dense spherical inflorescences on a pendulous stem, with male and female flowers on separate stems. the fruit matures in about 6 months, to 2–3 cm diameter, and comprises a dense spherical cluster of achenes with numerous stiff hairs which aid wind dispersal; the cluster breaks up slowly over the winter to release the numerous 2–3 mm seeds. the london plane is one of the most efficient trees in removing small particulate pollutants in urban areas.