This tree, commonly called the London plane is an interspecific hybrid between P. orientalis and P. occidentalis. There are theories that it originated as a variant or intraspecific hybrid within P. orientalis. The tree is also known by the synonyms P. x hispanica and P. x hybrida.
A number of varieties may be included under this name, though some may also be placed directly under Platanus. Bean, in 'Trees and shrubs hardy in the British Isles' uses the term 'London plane' to refer to a single distinctive clone commonly found in some parts of London. Since the common name is generally used to refer to all forms of the hybrid, I refer to this distinct clone as the 'London Form' and an account of it can be found on its separate web page. See the section on the naming of the London plane on this site. Most trees in London belong to this hybrid species.
Subspecies and varieties
There are many other forms, including some that are listed under P. orientalis. Not all of them have been identified in cultivation in London.Tree - It always makes a large tree, strong growing in London, often with a single clear stem to some height. A few trees have trunks that become swollen in strange patterns at the base of the trunk or sometimes a little way above the base.
Bark - This is usually but not always flaking in patches in all wood more than a few years old, leaving a dappled trunk. In some forms the bark may not shed freely, and the trunk becomes rugged, though flaking continues on younger wood.
Crown - The branching pattern is variable, most often sinuous branches are found, but sometimes they are straight. Some forms have pendulous lower branches, and the tips of the branches may hang down.
Shoot and young leaves - These are covered in down. They are moderately affected by anthracnose and most early leaves are damaged by this in London.
Leaf shape - Leaves are variable in shape, even on the same tree, 3, 5 or 7 palmate lobes, central lobe usually as long as wide, sometimes longer, toothed, sometimes sinuate. The leaf base is varied, truncate to cordate. Down is retained on veins and axils on the undersides of leaves. The range of variation in leaf shape could in some forms result in confusion with both the occidental and the oriental plane.
Leaf colour - This is variable, medium to dark green, paler below, matt to glossy on the upper part of the leaf.
Fruits - These are borne in groups of 1-4 on a stem on short lateral growths, and they can be up to 45 mm across, depending on variety.
The range of variation in this hybrid species is considerable. Because of crossbreeding with P. orientalis a range of forms that merge gradually into P. orientalis is likely to exist. Some forms (such as Pyramidalis) are thought to be quite close to the American plane.
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19-Feb-2007