Tree Keys Help Page

Suggestions for Using the Tree Keys

The Tree Keys are set up in a format that features a series of choices arranged in pairs (dichotomous). While this key includes most of the native and naturalized tree species commonly found in the northeastern United States, it is by no means exhaustive in scope. At times, it may be wise to consult specialized references.

Special Note: The keys use grammar and syntax that can be difficult to understand at first.

Example:

77.

Tree with bushy habit of growth; twigs with characteristic licorice-like taste, generally reddish-brown, more or less pale-woolly at lest toward apex; lateral buds blunt, more or less pale-woolly.

Malus sylvestris,
Apple

In these paragraphs, semicolons (;) are used to the separate discussion of different structures (i.e. -- "tree", "twigs", etc.), whereas commas (,) are used to list traits of these structures (i.e. -- "reddish-brown", "blunt", etc.). So, in the example above, the twigs are both reddish-brown and pale-woolly towards the apex, whereas the lateral buds (description preceded by a semicolon) are blunt and less pale-woolly.

General Instructions for Using the Keys
Start at the first pair of choices (indicated with the same number and background color). Choose the appropriate option by clicking with your mouse the number or word located to the extreme right.
Example:

1. Leaves persistent and green throughout winter (evergreens). 2

1. Leaves not persistent and green throughout winter (dead leaves often persistent in the oaks and beeches). 11
Continue making choices and progressing through the key. The main portion of the key is composed of three pages. You may scroll between these pages using the clickable prompts located at the bottom of the pages.
Example:
Eventually, and often after a long series of choices are made, you will reach the end of the key. The keys terminate in either a link to a separate genus key (i.e. -- Pinus sp.) or a link to a definite species in the Plant Pages database (i.e. -- Catalpa speciosa).

Example:

Leaves, except scale-leaves, needle-shaped,in definite, generally sheathed clusters on the sides of the branches.

Pinus sp.,
Pine

12.

Leaf-scars 2 or 3 at a node; bundle-scars in an ellipse; terminal bud absent.

Catalpa speciosa,
Northern Catalpa

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