Winter Botany Study, Part 5a: Kentucky Coffeetree

What a wonderful find in Albuquerque! While waiting for Roy to visit his doctor, Luna and I set off on a neighborhood walk within sight of the Balloon Fiesta park. We watched as 6 hot air balloons played in the early morning air currents, which caused me to look up. And there, right next to the sidewalk was a peculiar looking tree loaded with seed pods. I knew immediately the pods belonged to the legume family, but they were bigger than any I’d seen before. Big, big pods, clattering in the morning breeze, and luckily a handful within reach. So curious about this peculiar somewhat stumpy looking tree with grey bark flaking away from the main trunk like fat book pages, I grabbed half a dozen while Luna looked bored. But I was anything but bored. Time to geek out!

Excited to get home with my discovery, I immediately began researching answers to my questions, and the inevitable follow-up questions that led me down many rabbit trails.

The most important thing I learned, after confirming the tree was a native Kentucky Coffeetree, was that the pods and seeds (and leaves, when present) are toxic! So no taste testing. But wait …. early settlers in the Appalachian Mountains used to roast the seeds and brew a chicory flavored coffee. Fortunate for them the roasting process neutralizes the cytisine toxin. (More fortunate that real coffee beans finally made it to North America.)

But wait ……. Native Americans used the pulp inside the pods to treat insanity. And …… Native Americans brewed a tea from the leaves and pulp that was used as a laxative. And ….. cattle have been known to die after drinking from water holes with fallen leaves and pods.

Oh my gosh, golly goodness!

Note to self: Whether it was a coincidence or not that I experienced an “exquisitely” painful stomach ache after my day of seed pod dissection, remember to use gloves when handling the pods and seeds next time!

Interesting Stuff

Now for a bit of Paleobotany: The Kentucky coffeetree is considered an example of evolutionary anachronism (a new term to me which I explain below). Because the tough, leathery seed pods are too difficult for many animals to chew through (in addition to being poisonous) and they are too heavy for either wind or water dispersal, paleobotanists believe the tree leaves and seed pods may have been browsed upon by now-extinct mammalian megafauna. While munching, they would’ve nicked the seeds with their large teeth, breaking the very hard seed coat, aiding in germination. If this was the case, the prehistoric range of the Kentucky coffeetree may have been much larger than it was in historical times. Today, in the wild (and in the absence of large herbivores), the tree only grows well in wetlands where seed pods can rot and the soaked seeds can germinate.

Evolutionary anachronism refers to attributes of species living today that are best explained as a result of having been favorably selected in the past due to coevolution with other biological species that have since become extinct. So the Kentucky coffeetree, seed pods and all, coevolved with large prehistoric herbivores. When those herbivores became extinct, the natural attributes of the coffeetree appear as unexplained energy investments by the coffeetree, with no apparent benefit to the survival of this species. Hmmmmmm! Seems to make sense. I’m going to investigate further by reading The Ghosts of Evolution (2000) by Connie C. Barlow, who named evolutionary anachronism as a concept in evolutionary biology. Fascinating stuff!

After thoroughly enjoying the research (and there’s so much more I discovered about this tree species), I really enjoyed recreating watercolor pencil renditions of the beautiful seedpods, inside and out, and the seeds, inside and out). And after whacking a few seeds with a hammer (not too hard lest the innards become yellow dust) I’m going to germinate a few and grow myself a Kentucky coffeetree!

For more about the Kentucky coffeetree, read the notes included in my journal page. Please let me know if you enjoyed this kind of information -dense post, and would like to see more. Meanwhile, stay tuned for updates on my germination attempts. If successful, there should be seedlings in 2-4 weeks.