ID Keys

Dichotomous Leaf Key

So far you have made the following choices...

	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.

My leaf is from a tree

My leaf is from a shrub

My leaf is from a bramble, rose, or soft-wooded shrub with arching canes

My leaf is from a climbing or scrambling vine

	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.

Broad leaves

Slender or scaly leaves

My leaf is palm-like

My leaf is slender and strap-like (the yuccas)

I have a cactus, with leaves that are reduced to spines

Slender or Scaly Leaves

Long and slender needles can be single or in clusters.

Short, stiff needles can be scale-like or sharp and awl-like.

Needle-like, long and slender

Scale-like or awl-like (short, sharp and stiff)

Single or Clustered Long Slender Leaves?

Trees with single needles can be distinguished by how the needles are attached to the twig. Yew and Douglas-fir have tiny petioles (leaf stalks). Spruce needles grow on woody pegs. Firs have a swollen "suction cup" at the base of the needle.

Pines have needles in clusters or bundles called fascicles. A quick and easy way to distinguish between the pines is to count the needles in the fascicle.