Common Macrolichens of the Pacific Northwest

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Identification Key

Using this probabilistic key requires a different approach than using the more common dichotomous key. In a dichotomous key, the user travels through a tree of questions and branches, hopefully finally ending at 'THE' species. Any unanswered question requires the user to continue down multiple branches. This can be particularly frustrating if a question is unanswerable (Ex. 'Is this fruit red?' during flowering season). It is also difficult to capture the large variability of lichens in a dichotomous key.

In this probabilitic key, variations can be reflected as probabilities. For example, a species may not always have soredia - so the answers to the question of 'Soredia present?' could be assigned '80% Yes' and '20% No'.

This key allows the user to choose what questions/characteristics to select. The ongoing results are:

  • Most likely species out of the 240+ species covered (aka 'Score')
  • Most discriminating characteristics of those remaining (aka 'Stars')
  • How likely the selected characteristics occur in these 240+ species (aka 'Fit')

Like all keys, this key requires the user to understand some very specific terminology. Each selectable characteristic is described with photos on the Characteristics page. If you don't understand a term in the key, each chacateristic listed will link to the corresponding section on the Charateristics page.

For step-by-step instructions, see Suggested Steps .

Ready? Go to the Key .

    Known Bugs:
  • If 'Lobe Width' is in 'Most Discriminating Characteristics', then entering a Lobe Width value in the 'All Characteristics' section will be ignored. Workaround: enter 'Lobe Width' in the 'Most Discriminating Characteristics' section.
As this is a work in progress, any feedback is much appreciated. Thanks!