Key to common UK street trees

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The key allows quick but reliable identification of common urban street trees in the UK. Please make comments on the discussion page of this key (see tab above page) or send suggestions to Bob Press.


Key to common UK street trees — Bob Press
Geographic Scope: Britain — Audience: General public and advanced school children — Collaboration: open — Status: Text completed, illustrations incomplete, Species page incomplete (species links in red are not yet created). — Contributors: Bob Press, G. Hagedorn (formatting and minor adaptations)
1
Scale-like leaves (Calocedrus decurrens)
Leaves broader, not scale-like or overlapping   ► 3
2
Female cones
Branchlets
3
4
5
Leaves green above, silvery white beneath   Silver Maple
Acer saccharinum
Daniel Fuchs.CC-BY-SA.Acer saccharinum.jpg
Leaves of similar green on both sides   ► 6
6
Leaf lobes with numerous, small teeth; flowers in pendent clusters; fruits with wings more or less forming a right angle (at 90º to each other)   Sycamore
Acer pseudoplatanus
Acer pseudoplatanus5 ies.jpg
Leaf lobes entire, or with few, large teeth; flowers in erect clusters; fruits with wings horizontal (at 180º to each other) or nearly so   ► 7
Acer platanoides fruit black background JR Press.jpg
7
Leaves up to 8 cm long, lobed more than half-way to the base, the lobes with obtuse tips; flowers appearing with the leaves   Field Maple
Acer campestre
Acer campestre single leaf grey background JR Press.jpg
Leaves > 8 cm long, lobed less than half-way to the base, the lobes with acuminate tips; flowers appearing before the leaves   ► 8
8
Leaf lobes toothed   Norway Maple
Acer platanoides
Acer platanoides single leaf grey background R Press.jpg
Leaf lobes entire   Cappadocian Maple
Acer cappadocicum
Acer cappadocicum single leaf grey background JR Press.jpg
9
Leaves palmately divided, the leaflets radiating from a central point   ► 10
Leaves pinnately divided, the leaflets in two rows   ► 11
10
Flowers mostly white, with red and yellow blotches; fruits with numerous, sharp spines; winter buds very sticky   Horse-chestnut
Aesculus hippocastanum
Aesculus hippocastanum fruits JR Press 726a.jpg
Flowers red or bright pink; fruits with few, if any, blunt spines; winter buds not sticky   Red Horse-chestnut
Aesculus carnea
Aesculus carnea fruits JR Press 724a.jpg
11
Fruits 1 per stalk   ► 12
Fraxinus excelsior fruit grey background JR Press.jpg
Fruits paired on each stalk   Ash-leaved Maple
Acer negundo
Acer platanoides fruit grey background JR Press.jpg
12
Leaves with 7-13 leaflets; flowers appearing after the leaves, purplish, without sepals or petals; fruits 2.5-5 cm long   Ash
Fraxinus excelsior
Fraxinus excelsior flowers 4a JR Press.jpg
Leaves with 5-9 leaflets; flowers appearing after the leaves, white, with 4 narrow petals; fruits 1-5-2.5 long   Manna Ash
Fraxinus ornus
Fraxinus ornus flowers 160a JR Press.jpg
13
14
Twigs spiny at base; flowers with 5 unequal petals, pea-like   False Acacia
Robinia pseudoacacia
Robinia pseudoacacia stilplar thorns JR Press 836b.jpg
Twigs not spiny; flowers with 5, equal petals, not pea-like   ► 15
15
Leaves completely divided into 6 or more pairs of leaflets   ► 16
Lower part of leaf divided into 1-4 pairs of leaflets, upper part lobed but not completely divided   ► 17
Sorbus hybrida single leaf grey background JR Press.jpg
16
Ripe fruits entirely orange-red to vermillion-red (occasionally yellow), with yellow pulp   Orange-/Vermillion-fruited Rowans
Sorbus species
Sorbus aucuparia fruits JR Press.JPG
Ripe fruits white to pink or crimson, with white pulp   White-/Pink-/Crimson-fruited Rowans
Sorbus species
Sorbus glabrescens.jpg
17
Leaves with 1-2 pairs of leaflets, matt green above, grey-white woolly beneath; ripe fruit scarlet   Swedish Service-tree
Sorbus hybrida
Sorb-hybr.jpg.jpg
Leaves with 1-4 pairs of leaflets, glossy green above, thinly white hairy beneath; ripe fruit brownish-red   Thuringian Service-tree Sorbus thuringiaca
18
Leaves evergreen, often spiny   Evergreen Oak
Quercus ilex
Quercus ilex leaves black background JR Press 811a.jpg
Leaves deciduous, never spiny   ► 19
19
Twigs spiny (spines sometimes very few)   ► 20
Crataegus persimilis spines JR Press 425.JPG
Twigs not spiny   ► 24
20
Leaves not lobed; spines on twigs 3-8 cm   ► 21
Leaves lobed to more than one-third of the way to the base; spines on twigs 1-2.5 cm   ► 23
21
Leaves with a rounded or bluntly pointed tip, completely hairless beneath; flower and fruit stalks hairless   Cockspur-thorn Crataegus crus-galli
Leaves with an acute tip, hairy at least on veins beneath; flower and fruit stalks hairy   ► 22
22
Leaves with whitish hairs scattered over the whole of the lower surface; flowers c. 2.5 cm across; ripe fruits orange-red   Hybrid Cockspur-thorn
Crataegus x lavallei
Crataegus lavallei fruits JR Press C1.jpg
Leaves with hairs on the veins of the lower surface only; flowers c. 1.5 cm across; ripe fruits red   Broad-leaved Cockspur-thorn
Crataegus persimilis
Crataegus persimilis fruits JR Press 818.JPG
23
Leaves usually with 5-7 lobes, the largest reaching more than two-thirds of the way to the midrib; flowers always white; styles and nutlets1   Hawthorn
Crataegus monogyna
Crataegus monogyna single leaf grey background JR Press 576a.jpg
Leaves usually with 3 lobes, the largest reaching less than two-thirds of the way to the midrib; flowers white, red or pink; styles and nutlets 2-3   Midland Hawthorn
Crataegus laevigata
Crataegus laevigata single leaf grey background JR Press 3.jpg
24
Leaves lobed   ► 25
Leaves sometimes toothed but not lobed   ► 30
25
Leaves palmately lobed   London Plane
Platanus x hispanica
Platanus hispanica single leaf black background JR Press 706a.jpg
Leaves pinnately lobed   ► 26
Quercus cerris folliage.jpg
26
Leaves lobed to less than one-third of way to midrib; underside with a dense felt of hairs   ► 27
Sorbus intermedia leaf JR Press 626.JPG
Leaves lobed at least one-third of way to midrib; underside sometimes hairy but not densely felted   Oaks Quercus species
  ►► 28
27
Leaves whitish or silvery hairy beneath   Whitebeam
Sorbus aria
Sorb-aria.jpg
Leaves greyish to yellowish hairy beneath   Swedish Whitebeam
Sorbus intermedia
Sorb-int.jpg
28
Leaves with 7-9 pairs of blunt-tipped lobes, rough above, hairy beneath; acorn cup with spreading or reflexed scales   Turkey Oak
Quercus cerris
Žir.jpg
Leaves with 3-5 pairs of whisker-tipped lobes, smooth and hairless on both sides; acorn cup with short, close-pressed scales   ► 29
Quercus rubra 2008 07 06 (1).JPG
29
Leaves barely longer than wide, lobed c. half-way to midrib, shiny on both surfaces   Scarlet Oak
Quercus coccinea
Quercus coccinea Fe1aJPG.jpg
Leaves much longer than wide, lobed c. two-thirds of way to midrib, matt on both surfaces   Red Oak
Quercus rubra
Autumn Red Oak Leaf.jpg
30
Bark creamy white or silvery white   ► 31
Bark grey or brown   ► 32
31
Bark silvery, developing black, diamond-shaped fissures with age; twigs and smaller branches weeping; leaf stalk smooth   Silver Birch
Betula pendula
Betula pendula bark JR Press 870a.jpg
Bark creamy white, peeling in thin sheets; twigs and smaller branches erect or drooping at tips only; leaf stalk hairy   White Himalayan Birch
Betula jacquemontii
Betula jacquemontii barkJR Press 622a.jpg
32
Tree weeping; leaves > 10 times as long as wide   Weeping Willow
Salix x sepulchralis
Salix sepulchralis tree JR Press 443.JPG
Tree not weeping; leaves < 10 x as long as wide   ► 33
33
Leaves with wavy, entire margins   Beech
Fagus sylvatica
Fagus sylvatica leaves 395a.jpg
Leaves with flat, toothed margins   ► 34
34
Petals yellowish or absent; fruit dry   ► 35
Petals white, pink or red; fruit fleshy   ► 42
35
Fruits resembling small woody cones which persist on the tree all year   ► 36
Alnus cordata fruits JR Press 749.JPG
Fruits not cone-like, falling from the tree in autumn   ► 37
36
Leaf margins toothed; cones in clusters of 1-3   Italian Alder
Alnus cordata
Alnus cordata fruits JR Press 750.JPG
Leaf margins doubly-toothed (the teeth themselves toothed); cones in clusters of 3-8   Common Alder
Alnus glutinosa
Alnus glutinosa fruit JR Press 688.JPG
37
Flowers and fruits in pendent catkins; petals absent; fruits each with a membranous wing   Hornbeam
Carpinus betulus
Carpinus betulus fruits 375.JPG
Flowers and fruits in stalked clusters; petals present; entire fruit cluster attached to a single, membranous wing   Limes
Tilia species

  ►► 38
Tilia petiolaris fruits JR Press 854.JPG
38
Geschlossene Blütenknospen der Sommerlinde.JPG
39
Leaves with matt upper surface, the hairs in the vein angles beneath whitish; fruit rounded at both ends   Common Lime
Tilia x europaea
Tilia x europaea leaf hairs JR Press.jpg
Leaves with glossy upper surface; the hairs in the vein angles beneath reddish; fruit tapering at both ends   Caucasian Lime
Tilia x euchlora
Tilia x euchlora leaf hairs JR Press 2.jpg
40
Leaves green on both surfaces   Large-leaved Lime
Tilia platyphyllos
Tilia platyphyllos.jpg
Leaves dark green above, silvery white beneath   ► 41
41
Branches weeping   Weeping Silver Lime
Tilia 'Petiolaris'
Tilia petiolaris tree JR Press 277.jpg
Branches not weeping   Silver Lime Tilia tomentosa
42
Flowers with 3-5 styles; fruit with several seeds; bark without horizontal bands of pores   Crabs
Malus species

  ►► 43
Malus purpurea halved fruit JR Press.JPG
Flowers with a single style; fruits with a single seed (stone); bark often with conspicuous horizontal bands of pores ( lenticels  Cherries
Prunus species

  ►► 46
Prunus cerasifera halved fruit JR Press.JPG
43
Leaves strongly tinged with purple; flowers dark or ruby red; fruit purplish red   Purple Crab
Malus purpurea
Malus purpurea 42a flowers JRPress.jpg
Leaves green; flowers pink or white; fruits red or yellow   ► 44
44
Leaves hairy beneath; flowers pale pink fading to white, usually with 4 styles; fruits yellow   Japanese Crab
Malus floribunda
Malus floribunda (Japanese crabapple).jpg
Leaves hairless or hairy only on the veins beneath; flowers white, with 5 styles; fruits flushed with or entirely red   Siberian Crab
Malus baccata
Malus baccata var hymalaica1.jpg
45
Flowers and fruits arranged in spreading or drooping spikes of 10 or more   Bird Cherry
Prunus padus
Prunus padus flowers.jpg
Flowers and fruits solitary or in clusters of 10 or less   ► 46
Prunus serrulata 2005 spring 026.jpg
46
Leaf margin with blunt and rounded teeth; flowers solitary, rarely in clusters of 2-3; fruit 2-3 cm   Cherry-plum
Prunus cerasifera
Prunus cerasifera fruit JR Press 904.jpg
Leaf margin with sharply pointed teeth; flowers in clusters of 2-6; fruit < 1.5 cm   ► 47
47
Leaf margin with teeth gradually narrowed into a long point tipped with a long, fine bristle   Japanese Cherry
Prunus serrulata
Prunus serrulata marginal teeth JR Press.jpg
Leaf margin with teeth rounded or narrowed into a point but not tipped with a long bristle   ► 48
48
Leaf stalk hairy; flowers generally pink, the stalk 1 cm   Spring Cherry
Prunus subhirtella
Prunus subhirtella a2.jpg
Leaf stalk smooth; flowers white, the stalk 2-5 cm   Wild Cherry
Prunus avium
Sweet cherry flower.jpg


The key is also available in a version for young school children.


Glossary (unfinished work)

acute Describes a leaf apex where the two edges forming the tip make an angle up to 90 degrees.

acuminate Describes a leaf apex which is long and tapered to a sharp tip.

alternate: Arrangement where the first leaf is borne on one side of the stem, the next leaf on the other side and so on.

catkin A cylindrical inflorescence of usually wind-pollinated flowers which lack sepals or petals.

compound Composed of several entirely separate parts. Compound leaves are made up of three or more leaflets. (See the gallery of images below.)

deciduous A tree which sheds its leaves all at once in autumn. It can also refer to parts of the plant which are shed early, e.g sepals.

entire Without any teeth, lobes or indentations.

evergreen A tree which retains its leaves all year round.

graft An artificial joining of one plant onto another.

foliage All the leaves and twigs together.

inflorescence All of the flowers and their arrangement.

infructescence All of the fruits and their arrangement.

leaflet A subdivision of a leaf.

lenticel Pore in bark allowing gases to pass in to and out of the trunk and branches.

native A tree occurring naturally in an area.

introduced A tree brought into an area by humans.

midrib Main vein running up the centre of a leaf blade.

obtuse Describes a leaf apex where the two edges forming the tip make an angle between 90 and 180 degrees.

opposite Arrangement of leaves in pairs, with one leaf on either side of the stem.

palmate With divisions radiating from a central point, like fingers spreading from the palm of a hand.

pinnate With divisions arranged in two parallel rows.

pollard A tree where the upper branches have been cut to encourage new growth.

simple Not divided into leaflets or lobes, opposite of compound. (See the gallery of images below.)

spike A long, narrow arrangement when referring to an inflorescence or infructescence. Spikes can be cylindrical, conical, branched or simple.

style Usually long and slender structure on top of the ovary and bearing the stigma.


Compound leaves

Simple leaves