Plane trees of London
Platanus x acerifolia 'Augustine Henry' |
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This cultivar forms a well-shaped tree, usually with a prominent straight central trunk and regular branching when it is allowed to grow freely. It can usually be distinguished by its crown shape, its winter buds, and large leaves.
Specimens of this variety can be found infrequently through Greater London. A selection is described here. Most are young or youngish, but there are a few older specimens, including the mature tree at Kew Gardens which may have been the first described under this name.
William Bean lists this under Platanus; he does not list it as a form of the London plane. However, the European Garden Flora lists this variety as a form of Platanus x acerifolia. Other authorities have at times ascribed it to the species P. californica (not a recognised name), P. racemosa, and P. occidentalis, and at least one to P. orientalis, though none of these are very likely.
It is named after the plantsman Augustine Henry (Wikipedia article) , who among his other activities, carried out some early investigations into the origin of the London plane. This variety was first described by Henry, as Platanus hispanica, from the specimen at Kew Gardens.
Tree and crown - It forms a large strong growing tree, usually with a single clear upright trunk to a considerable height. The trunk is usually straight and more cylindric than most plane trees. The branches are somewhat sinuous. The tips of side branches droop to the extent that the tree can seem a weeping form.
Bark - This flakes freely in patches on trunk and older branches, leaving a dappled trunk. On younger trees it is sometimes somewhat persistent, especially on the lower trunk, with regular fractures.
Shoot and unfolding leaves - These are covered in down as in all planes, shed on mature tissue. They are moderately affected by anthracnose and many early leaves are damaged by this in London. A red flush can be seen in the stipules and young shoots, changing to a brown flush as the shoot matures.
Axillary (leaf) buds - The buds are long and pointed like beech buds in winter, dark purple-red in colour. They can be up to 18mm long by 8mm wide, but typically are 9-11mm by 5-6mm. In summer if green leaves are pulled off, the forming bud may not be any longer at that time than in other forms, but still is sharply pointed and often has a clearly visible long conical shape.
Stipules - These are long, up to 50mm end to end, and with the sheath round the stem being up to 13mm long. They can be found persisting on the shoots into later summer.
Leaf - Leaves are commonly found with 5 palmate lobes (sometimes 7 and occasionally 3 lobes). The central lobe usually slightly longer than wide, with many teeth. The base of the leaf blade is varied, but is often truncate. Leaves are thin and large, up to 40cm wide x 35cm long, sometimes bending or folding lengthwise . On leaves that have the main leaf blade held horizontally, the side lobes can droop. The petioles are up to 9cm long. (Most other forms seen in London have smaller leaves.)
Leaf colour - The leaf is a matt green above, paler below, darkening somewhat through the season.
Fruits - These are borne in groups of 1-3 on a stem on short lateral growths. They are often sparse, and may be difficult to find on some trees. The fruits are smaller than in most other hybrid planes.
This tree makes a fine, well-shaped tree, with a clear and prominent leader, and attractive foliage. It should be planted more frequently in parks and landscape settings where there is room for a large tree that can be allowed form its natural shape. It is not always listed in grower catalogues. However, it has been distributed in recent decades, as trees planted in the 1990's can be found in several parks, and in some roadside plantings.
Click on any image to see it in full detail
Shoots in late August. Note that the lateral lobes droop below the line of the central lobes.
Flowers of both sexes can be seen clearly in this image.
The young leaves are similar to those of many other planes. When affected by anthracnose as in this image, the shoots can however appear to be rather sparse compared with other forms.
Trunk of a tree that is believed to be about 20 years old at the time of photography (2009, in Victoria Park, Bethnal Green). Note the characteristic bark pattern found in many young trees.
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12-Oct-2022