ID Keys

Dichotomous Leaf Key

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Location: NC

	A tree generally has a single upright stem and reaches a height of 20 feet. Some species are shrubs in harsh climates and trees in moderate climates.
	Shrubs are low branching, suckering, or have multiple stems and do not reach 20 feet in height.
	Most people recognize brambles, which include roses and blackberries.
	Vines require some extra help for support. They hold on to the support by twining, growing tendrils, or aerial roots.

	Cacti do have leaves - they are reduced to spines.
	Palms are common in warm regions.
	Yuccas can be found in many loacations but are more common is deserts.
	Slender or Scaly leaves can be found on pines, junipers, and other genera.
	Broadleaf includes genera with narrow leaves, such as the willows.

Broadleaf Arrangement, or phyllotaxy, is a very important id clue. To determine phyllotaxy, look to see how many leaves are attached to the twig at each node. If there are no leaves, look for the arrangement of the buds that can be found at the base of each leaf. If you can not reach the twigs, remember that twigs grow from buds... and they will have the same arrangement as the leaves.

	Most woody plants are alternately arranged. The leaves and buds alternate along the stem.
	These leaves are oppositely arranged, as are the buds that grow at the base of the leaves.
	A few species have whorled leaves, with (usually) 3 leaves and buds at each node.

Broadleaves can be simple or compound. Simple leaves have a single blade, compound leaves have several leaflets attached to a common stalk. It can be difficult to distinguish between these two leaf types. It may help to determine what, exactly, is the deciduous unit. Leaves are attached directly to twigs; leaflets are attached to a common stalk that is attached to the twig. Another clue... in late summer, buds can be found on the twig at the base of the leaf. There are never buds on leaf stalks.

	A leaf with a single blade is a simple leaf. The leaf stalk is attached directly to a woody twig.
	The simplest type of compound leaf is a bifoliate leaf, which has two leaflets attached to a common stalk.
	Trifoliate leaves have three leaflets attached to a common stalk.
	Palmate leaves have leaflets that radiate from the end of the central stalk.
	Pinnate leaves have leaflets attached laterally to the central stalk.
	Bipinnate leaves have pinnate leaflets attached to pinnate leaflets. The whole structure is shed in the fall.

Broadleaf Shape is generally considered in outline.

	Heart-shaped, or cordate
	Triangular, or deltoid
	Long and Narrow, or Lanceolate
	Oval, widest above the middle (Obovate)
	Oval, widest below the middle (Ovate)
	Round in Outline
	Wedge-shaped