York County Envirothon 3rd-4th Leaf Key: Backyard Species
Directions: Choose a leaf or branch to identify from your “3rd-4th grade York County Envirothon
Study Species for 2015”. Read the two choices at number 1. Choose which choice, a or b, is
the most like your sample. Go to the number listed after your choice. Continue following the
numbers of the key until you find the name of your sample.
1a. The leaves are evergreen.... go to 2
What is a dichotomous key?
1b. The leaves are deciduous…. go to 3
A tool for identifying plants
or animals based on choices
between alternative
characteristics. Dichotomy is
the distinct difference
between two things.
2a. The leaves are needle-like…. go to 4
2b. The leaves are scale-like…. Eastern Red Cedar
2c. The leaves are broad with sharp, pointed teeth….
American Holly
3a. Leaves are arranged oppositely on the branch.… go to 5
3b. Leaves are arranged alternately on the branch…. go to 6
4a. The needles are in bundles of 5 and 2.5-5 inches long…. Eastern White Pine
4b. The needles are single, short, flat, and have two white stripes on the underside…. Eastern
Hemlock
5a. Leaves are lobed…. Go to 14
5b. Leaves have no lobes…. Flowering Dogwood
6a. The leaves are compound…. go to 7
6b. The leaves are simple…. go to 8
7a. The leaves are pinnately compound…. go to 9
7b. The leaves are palmately compound…. go to 10
8a. Leaf margins are entire or smooth…. Eastern Redbud
8b. Leaf margins are toothed or bristle tipped.… go to 11
9a. Each leaflet is oval or elliptical in shape.… Black Locust
9b. Each leaflet is lance shaped…. Black Walnut
10a. Typically three leaflets per leaf…. Poison Ivy
10b. Typically five leaflets per leaf…. Virginia Creeper
11a. Leaves are palmately veined…. go to 12
11b. Leaves are pinnately veined…. Go to 13
12a. Leaves have fine teeth, and are star-shaped with five pointed lobes…. Sweetgum
12b. Leaves have coarse teeth with 5-7 lobes…. Sycamore
13a. Leaves are oval with 7-9 lobes and bristle tips…. Red Oak
13b. Leaves are oval with fine teeth and no bristle tips or lobes…. Bradford Pear
14a. Leaves usually have three lobes…. Red Maple
14b. Leaves usually have 5-7 lobes.… Norway Maple