Let’s play Name That Tree!

As a botanist, I may be biased, but I think part of the reason most people get more excited about animals than plants is that we grow up with a language for them, an awareness of the details that make each creature unique and therefore worthy of our interest and excitement.  For plants, for many of us, they remain just plants. Or possibly in three categories: flowers, plants and trees. But, as I learned to recognize the details and patterns and relationships that define the plants, plants became more interesting.

Okay, perhaps I loved learning the language of plants because I am a huge nerd. Not perhaps, definitely. But, I do believe that the more people learn about plants and their patterns, the more interested they become. I’ve taken many lucky friends out on hikes where I gush about this little beauty and that cool shrub, and usually, my enthusiasm can rub off just a bit, as they learn a few plants. Our brains are built for patterns and problem solving, learning to identify plants is just one more (fun!) game.

The basic tool that botanists use to identify plants is called a dichotomous key. Basically, the key is an ordered list of 2-option questions, which, as you answer in sequence, lead you to the correct identification of your plant (or bird or rock formation or pretty much anything)  The questions can as simple as “Does it have leaves or does it have needles?” to as complicated as:

16-Pappus of awns with reflexed barbs; phyllaries in 2 series, unarmed ….. BIDENS {G3,11}

16′– Pappus 0 or of smooth or minutely rough bristles or narrow scales; phyllaries graduated in 6+ series, often fringed or spine-tipped (see also Volutaria canariensis….. CENTAUREA {G1,4} (From group 2 of the Asteraceae key in the Jepson Manual of California Flora)

To work with a technical key like the Jepson Manual quotes above, you have to learn the language; what is the pappus or the phyllaries? (If you really want to know, here’s a diagram) With practice, you become fluent in the language of your botanical region, but, really, everyone still checks the glossary a lot, no matter how good they get. If you have to start from the very beginning of the key, Well, I have this plant, it will take a long time. If you learn the patterns and family relationships, you can cut down the line to the details, I know this plant is in the Aster family, but I don’t know which genus, it gets much easier.

So, I was talking with my sister about her job as a nature educator at a camp in the San Bernadino Mtns of Southern California, and how she has a hard time getting her students excited about plants.  We decided that maybe if they had a dichotomous key to use to identify the common trees, maybe they would get excited about discovering the identity of the species themselves. So, to test this theory, I agreed to try to build her a dichotomous key.

Here’s her list of common tree species in their woods: Ponderosa Pine, Jeffery Pine, Sugar Pine, Coulter Pine, Ponderosa Pine, White Fir, Douglas Fir, Juniper, Sequoia,  Incense Cedar, Black Oak, Live Oak, Aspen, Manzanita, and Mountain Mahogany.

Aspen and Ponderosa Pine Forest in the Spring Mountains, Nevada (with Charleston Peak in the background)

So, the first thing to do to build a key is to group the related trees together. Obviously, all the Pines are closely related, and the other plants that form seed cones, the Firs, are also related. Beyond that, the Juniper, Sequoia, and Ceder all join the pines in the larger group of plants, the gymnosperms. Gymnosperms form naked seeds, unlike the flowering plants, angiosperms, who grow seeds enclosed in a structure called an ovule. So, the first step of the key is flowering plants versus gymnosperms.

Beyond that, you can built a key from the critical characteristics that botanists use to break the plants down into families, genera, and species. However, these characteristics, like seed structure, are not always the most obvious traits when you look at a plant. So, botanists who built keys try to use traits that are easy to see, but still accurate.  For the key I designed for my sister’s students, it was hard to decide on traits that would be easy figure out, but also accurate. Luckily, there’s a relatively small number of tree species growing around her mountain home.

Emily tested out the first draft of her key with a smart group of 6th graders last week, and she said they really had fun being scientists who could identify plants. Once it become a puzzle that they could figure out, they wanted too. So that makes me happy. I finished this final version with some sketches to decorate and explain key terms. You can check it out below, if you like in Southern California mountains. If not, I recommend picking up a key to the trees and flowers in you area. Spring arrives, and brings the perfect time to play botany. Enjoy!

Here’s the key:


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