As you walk around the Whiteknights campus you can find at least twenty two species of maples, in the genus Acer (family Sapindaceae). They can be identified by their helicopter-like fruits, opposite branching, and mostly 5-lobed palmately veined leaves (Photos 1-3).
Helicopter-like Maple samaras
There are close to 200 Acer species known to botanists, so figuring out which one you are looking at can be a bit tricky, but once you learn the basic pattern you will be able to identify the genus.
Acer seeds are called samaras. They twirl like helicopters as they fall from the tree. The angle between the pair of seeds can also help you to identify the different species.
There are three species of Acer referenced in the most recent survey of the plants of Whiteknights campus (Photos 4-6). Acer campestre, the field maple, is the only native British maple.
Acer platanoides, the Norway maple and Acer pseudoplatanus, the Sycamore are naturalised, which means they have adapted to living here and can reproduce freely. They can be found both growing in the Wilderness among deciduous trees and shrubs and planted singly or in borders around the campus.
The other maples in the photo gallery have been planted on campus. The maples in photos 7- 11 show the typical 5-lobed leaf shape. You might not recognise the maples in photos 12-18 because their leaves have different numbers of lobes, but they all have opposite branching and helicopter-like samaras. Once you know what to look for, you will start seeing maples everywhere!
The plants in photos 19 and 20 are maple impostors! Their leaves are similar to maples, but theyhave alternate branching and their fruits are differently shaped.
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- Helicopter-like Maple samaras
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- 2) Maple twig showing opposite branching
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- 3) Palmate veins in a Sycamore leaf radiate out from one point.
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- 4) Field maple, Acer campestre
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- 5) Sycamore, Acer pseudoplatanus. The leaf is toothed along all of its edges and does not have sharp points.
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- 6) Norway maple, Acer platanoides. The leaf lobes have sharp points.
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- 7) Silver maple, Acer saccharinum, has leaves with deep lobes and large teeth.
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- 8) Sugar maple, Acer saccharum, is similar in shape to the Norway maple but with fewer teeth and longer points.
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- 9) Smooth Japanese maple, Acer palmatum, has highly dissected, toothed leaves.
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- 10) Shantung maple, Acer truncatum
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- 11) Cappadocian maple, Acer cappadocicum
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- 12) Montpelier maple, Acer monspessulanum, has 3-lobed leaves.
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- 13) Cretan maple, Acer sempervirens, has 3-lobed leaves.
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- 14) Moosewood, Acer pensylvanicum, has a 3-lobed leaf with finely toothed edges.
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- 15) Ash leaf maple, Acer negundo, has 3 leaflets. When the leaflets are close together, they look like a single 5-lobed leaf.
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- 16) Paper bark maple, Acer griseum, also has 3 leaflets which are more separated than those of Acer negundo.
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- 17) The bark of the paper bark maple, Acer griseum, peels off like the bark of the paper birch.
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- 18) Downy Japanese maple, Acer japonicum, has both 9- and 11-lobed leaves.
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- 19) Sweet Gum, Liquidambar styraciflua, is not a maple. How can you tell?
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- 20) London Plane, Platanus x hispanica (x acerifolia), has alternate branching and “itchy balls” as fruit. The bark peels away from the trunk leaving a mottled pattern. Acerifolia means maple-like leaves.
Photos and text may be used for non-commercial purposes.
Bibliography
Aas, G. and Riedmiller, A., 1994. Trees of Britain and Europe. London: Harper Collins Publishers.
Le Grice, D. and Jury, S.L., 2011. Flora of Whiteknights Park: A survey of the plants of the University of Reading Whiteknights Campus. Unpublished, University of Reading.
Sheridan Lawn and Landscaping L.L.C., 2012. Tree Species of the Acer Genus. [Online] Available at: http://www.treenames.net/ti/acer/acer.html. [Accessed 27 October 2012].
Stace, C., 2010. New Flora of the British Isles, 3rd edition. Cambridge: Cambridge University Press.
Sterry, P., 2007. Collins Complete British Trees. London: Harper Collins Publishers.
An epic blog – good work! I’d like to see the last few campus maple species added over the summer perhaps – and how about a blog on winter twig ID for Maples?
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