The London Plane tree (Platanus x hispanica (syn. x acerifolia) is a very common urban tree that is extensively planted in city parks, gardens and avenues. Although it is called the London Plane this tree is not native to England. In fact it is not native to anywhere as it is a hybrid of two trees from opposite sides of the globe. Its parent trees are the American Sycamore and the Oriental Plane. The hybrid was most likely a natural result of the two parent trees being planted close to each other in Spain (thus x hispanica). It has been very widely planted in England since the late 1600´s.
The tree in the image above is of a tall London Plane that I found in the royal gardens of Aranjuez (Spain). I estimate that this tree is about 7 feet (2 meters) wide at the base and over 120 feet (35 meters) tall. It is a fine example of the fact that this tree can reach very large proportions. The tree below has a more rounded shape that is more typical of this tree when it does not have to compete for light. It is located on the grounds of the Bonneville dam east of Portland Oregon on the Columbia River.
There is a great deal of variation in the appearance of different London Plane cultivars. Some of these have a closer similarity to the American Sycamore while others are more like the Oriental Plane and variants can be found that cover the full spectrum between the two parent trees. The picture below is of the Londan Plane tree fruit which looks like a small puff ball about one inch in size.
These fruits grow in groups of 1-4 as can be seen in the image below and they stay on the tree into the winter until they disintegrate and drop their seeds.
The bark of the London Plane has a cameoflage like apearance and is constantly flaking which reveals the lighter color bark beneath. This is said to help it survive in city environments where the polution is greater.
I´ve often seen older London Planes with large lumby boles on their trunks. In the Laurelhust park of Portland Oregen there are a group of these trees that are extremely lumpy and deformed looking (below).
The leaf of the London Plane is the logo of the New York City department of Parks and Recreation.
One interesting bit of trivia about this tree is that one of its older specimens is the most valuable tree in Britain. A plane in Mayfair has been valued at £750,000.