Identification keys

Identifying trees

Identification key of the principal trees in Quebec's urban regions.

Is this tree a conifer or a deciduous tree?

Conifers have needle- or scale-shaped leaves and their seeds are on a cone. If the tree is a conifer, see the conifer identification key.

Deciduous trees have wide leaves (wider than a needle) and lose their leaves in the fall. If the tree is deciduous, see the deciduous tree identification key.

Conifer identification key

Does the tree bear needles or scales?

• Needles:
  how are they attached to the twig?
  • If the needles are bundled,
    how many needles per cluster are there (a cluster is a small group of needles).
    • If there are 2, 3 or 5 needles per cluster --------------- it's a pine (Pinus).
    • If there are 10 needles or more per cluster -------------- it's a larch (Larix).
  • If the needles are single:
    Roll one between your fingers
    • If the needle rolls easily
      between the fingers (it's square) --––––––––- it's a spruce (Picea).
    • If the needle does not turn easily between fingers (it's flattened) ------------- it's a fir (Abies).
  • If the tree has scales
    • Are the shoots flattened? ----------- it's a thuya (Thuja)
    • If the shoots are rounded
      ------------ it's a juniper (Juniperus).

Deciduous trees identification key

If the tree is deciduous, look closely at its leaves to find out its genus.

Leaf parts

Base of the leaf: part of the leaf situated on each side of the petiole.

Bud: future leaf protected by scales that will spread open the following spring.

Leaflet: one of the sections of a compound leaf. It sometimes looks like a little leaf, but contrary to a leaf, there is never a bud at the base.

Leaf margin: the edge, contour of the leaf.

Veins: small channels in the leaf through which the sap circulates.

Petiole: stem by which the leaf is attached to the branch.

Leaf tip: the tip of the leaf is located opposite the point where the petiole is attached.

Branch: a secondary woody stem on which the leaves, flowers and fruits grow.

Are the leaves opposite or alternate?	Are the leaves simple or compound?
They are opposite if they are attached to the branch 2 by 2, facing each other.	A simple leaf is not divided into leaflets (it is in one piece).
They are alternate if they are not attached to the branch facing each other.	A compound leaf is divided into several leaflets.

• If your tree has opposite leaves (simple or compound), see group 1>
• If your tree has alternate and simple leaves, see group 2
• If your tree has alternate and compound leaves, see group 3

Group 1: Trees with opposite leaves

Does your tree have simple or compound leaves?

1. If the leaves of your tree are simple,
look at the leaf margin.

• If the leaf is whole (the margin is smooth),
  look at the size of the leaves.
  • If the leaves are large (10 to 30 cm) ---------------- it's a catalpa (Catalpa).
  • If the leaves are small ( 5 to 12 cm) -------------- it's a lilac (Syringa).
• If the leaf is lobed and toothed
  (yes, a leaf can be both at the same time... It can have toothed lobes)
  ------------ it's a maple (Acer).

2. If the leaves of your tree are compound,
look at the arrangement of the leaflets.

• If the leaves are compound-palmate
  ------------ it's a horse-chestnut (Aesculus).
• If the leaves are compound-pinnate
  look at the shape of the leaflets.
  • If the leaflets are regular
    (they are all the same shape)
    ------------ it's an ash (Fraxinus).
  • If the leaflets are irregular
    (they are not all the same)
    ------------ it's a Manitoba maple (Acer negundo).

Group 2: Trees with alternate and simple leaves

• If the leaves are lobed
  ------------ it's an oak (Quercus).
• If the leaves are lance-shaped (lanceolate: long and thin)
  ------------ it's a willow (Salix).
• If the leaves are cordate (heart-shaped)
  ------------ it's a linden (Tilia).
• If the leaves have a different shape, look at the base of the leaf, and go on to the next step.
  
  

  The leaf is asymmetrical if the base of the leaf is not the same on both sides of the petiole.

  The leaf is symmetrical if the base of the leaf is identical on both sides of the petiole.

  • If the base of the leaf is asymmetrical
    • Is the leaf oval-shaped?
      ------------ it's an elm (Ulmus).
    • Is the leaf tip very long?
      ------------ it's a hackberry (Celtis).
  • If the base of the leaf is symmetrical,
    look at the teeth on the leaf margin
    • If the leaf is double-toothed
      (each tooth bears smaller teeth)
      
      ------------ it's a birch (Betula).
    • If the leaf is single-toothed
      (there is one series of teeth),
      look at the petiole
      • If the petiole is long and flat ----------- it's a poplar (Populus).
      • If the petiole is round and short (less than 2 cm), look at the teeth and veins of the leaf.
        • If the teeth are pointed and always at the tip of a vein
          ----------- it's a beech (Fagus).
        • If the teeth are rounded and not always at the tip of a vein
          ----------- it's a cherry (Prunus), a plum (Prunus) or a crabapple (Malus).

Group 3: Trees with alternate and compound leaves

What size are the leaves?

• If the leaves measure more than 25 cm ----------------- it's a walnut (Juglans).
• If the leaves measure less than 25 cm, look at the leaflets.
  • If the leaflets are not all the same size and the one at the tip is bigger
    ----------- it's a hickory (Carya).
  • If there are many little leaflets, all the same size, look at the leaf margin of the leaflets.
    • If the leaflets are toothed
      ----------- it's a mountain ash (Sorbus).
    • If the leaflets are whole (the leaf margin is smooth),
      count the number of leaflets.
      • If there is an odd number of leaflets
        ----------- it's a locust (Robinia).
      • If there is an even number of leaflets
        ----------- it's a honey locust (Gleditsia).