Random access identification key covering over 200 species of Washington's deciduous trees, shrubs, and vines - including most of the common species - using characteristics of the twigs, buds, and bark that are visible during the winter, with supplementary characters for leaves and fruits that frequently persist on the plant or on the ground beneath.

To use this key, compare a twig sample against the characteristics given below and then select those characteristics that best match the sample. Click the Show Matches button to view a list of the species that match the selected characteristics. Characteristics are organized into categories, and within each category you can make one or more selections. If you are uncertain which character to select within a category you are better off leaving that category blank.