Platanus occidentalis, also known as American sycamore, American planetree, western plane,[3] occidental plane, buttonwood, and water beech,[4] is a species of Platanus native to the eastern and central United States, the mountains of northeastern Mexico, extreme southern Ontario,[5][6] and extreme southern Quebec.

In 1744, a Shenandoah Valley settler named Joseph Hampton and two sons lived for most of the year in a hollow sycamore in what is now Clarke County, Virginia.

The American sycamore is also well adapted to life in Argentina and Australia and is quite widespread across the Australian continent, especially in the cooler southern states such as Victoria and New South Wales.

American sycamore is found most commonly in bottomland or floodplain areas, thriving in the wet environments provided by rivers, streams, or abundant groundwater, though it will die after being flooded for more than two weeks at a time.

[18] Its life cycle follows the pattern of a "weedy" species: it grows mature enough to reproduce rather young and produces large numbers of wind-distributed seeds.

[21] The American sycamore is able to endure a big city environment and was formerly extensively planted as a shade tree,[11] but due to the defacing effects of anthracnose it has been largely usurped in this function by the resistant London plane.

Gnomonia platani), an introduced fungus found naturally on the Oriental plane P. orientalis, which has evolved considerable resistance to the disease.

Although rarely killed or even seriously harmed, American sycamore is commonly partially defoliated by the disease, rendering it unsightly as a specimen tree.

Cankers form on twigs and branches near infected leaves, serving to spread the disease by spore production and also weakening the tree.

[25] As a result of the fungus' damage, American sycamore is often avoided as a landscape tree, and the more resistant London plane (P. × hispanica; hybrid P. occidentalis × P. orientalis) is planted instead.

The sycamore made up a large part of the forests of Greenland and Arctic America during the Cretaceous and Tertiary periods.