How Our PC Keys Work


The interactive plant keys for PCs/Windows described here include all the vascular plants known to grow wild in the state or province (or larger region) for which the keys are available.  This includes all native or naturalized plants; all trees, shrubs, flowering plants,  grass-like plants, conifers, and vascular spore-bearing plants.

The keys are much faster and easier to use than traditional dichotomous keys.  They contain comprehensive descriptive data for each plant species, allowing the use of almost any plant feature to identify it.

To identify a plant, the user first selects from a hierarchical menu of types of plant characteristics (such as leaves, stem, inflorescence, flower or fruit).  The user then selects those characteristics which best describe the plant to be identified.  Each time a characteristic is marked as being true, the computer eliminates from consideration all plants for which that characteristic is never true, and the computer also identifies all menu choices which would not help to distinguish between the remaining species.  Characteristics may be marked by a choice of three ways, including marking directly on line drawings that illustrate the characteristics, as in the image below.


The user continues to mark selections of characteristics.  At any point, the user may ask the computer to analyze the remaining species and provide a list of the menus which are both easiest to use and will most effectively separate between the remaining species. The user may select from that list or go to a different menu.  There are no forced choices.


In addition, one may refer to an alphabetized list of the remaining species using either common or scientific names. From that list, one may select any species and access descriptive information, including color photographs for virtually all species, and the page numbers of references that describe each plant. It is also possible to call up a gallery of photos of the remaining species.  The user may at any time call up a list of the characteristics they have marked and change any marks.  If at any time the remaining species are of the same family or the same genus, the computer identifies that family or genus.  When all species are eliminated but one, the plant has been identified. The user may then check it against the photos and the references listed for that species.


One may also call up a gallery of images for a single species, and expand each image for full-screen viewing.


A Help program includes a User’s Guide with a Tutorial, and a Quick Reference Guide for first-time users.


There is also a series of tutorial videos, based on a weed key but with the same software platform, at