A dichotomous key is a useful tool that practically anyone can use for identifying plants. “Is the bark smooth? If so, go to step 5. Are the leaves serrated? If so, go to step 8. Your tree must be is a beech tree.” Of course, in a plant identification class, using this step by step plant identification key would be considered cheating. A good horticulturalist should have these steps memorized then, right? Actually, no.

The woody landscape plants identification lab is a class I’ve taught for six semesters now. As the course name infers, students learn identification features (e.g., leaf shape, bark color, fruit size, etc.) of plants typically used in landscape design. As part of their evaluation, students are required to correctly identify these plants by their common and botanical names, on the spot, as we walk through campus. Without a doubt, students’ greatest struggle at the start of this class is that they try to get by with memorizing a few ID features for each plant and forget to look at the big picture—to literally step back and consider context. This is what I call the mindless, “dichotomous key approach,” and it doesn’t work; nature doesn’t have a mold. For example, after having incorrectly identified a plant, a student will comment, “but that tree isn’t supposed to be crooked like that.” My reply is something along the lines of “…and that tree didn’t expect to get hit by lightning.”

Ellen J. Langer (2000) defines mindfulness as “a flexible state of mind in which we are actively engaged in the present, noticing new things and sensitive to context.” She asserts that how we teach may be more valuable than the material we are actually teaching. After having read Langer’s article, I had a teaching epiphany. My students don’t need a longer list of differentiating anatomical features to improve their ability to identify plants. They really just need to remember to think. From here on, my teaching strategy for this course will be geared more toward how to think about plant identification, rather than what to remember.

Have any of you had a similar experience in your field?

Literature Cited:

Langer, E.J. 2000. Mindful Learning. Current Directions in Psychological Science 9(6):220-223.