Plants that Harm & Heal

Hanson, T. 2015. The triumph of seeds: How grains, nuts, kernals, pulses & pips conquered the plant kingdom and shaped human history. New York: Basic Books.

For me, tea is so much more than a tasty beverage, and even more than an infusion of health-promoting benefits. Tea is a ritual. A meditation. A necessary component of starting and ending the day.

And now I see that the way that my tea-drinking habit connects me to the world of plants is even bigger than I could have imagined.

The tea I choose to start my morning with on any given day depends on what I hope to derive from it. Some days I’m looking for a subtle boost of energy, perhaps with tender, ground green tea leaves. Other days, especially if I’m feeling under the weather, I may prefer a soothing herbal tea with cooling peppermint, echinacea leaves and elderberries. And, if I’m looking for a combination of energy and warmth in the coldest part of the winter, my favourite choice is a spicy black chai tea, with spices such as cinnamon, cloves, cardamom, anise and ginger.

The section of Thor Hanson’s The Triumph of Seeds “Seeds Defend” (Chapters 8-11) is an in-depth look in to a few of the ways that seeds have evolved to protect themselves from those who want to feast on them and who may destroy their seeds’ ability to be dispersed and reproduce.

A theme that comes across to me in particular is how, because of these evolutionary changes, plants and their seeds are a huge part of our lives. As if this message hadn’t already been hit home with our reliance on plants for food, clothing, tools and other materials, I am also now much more aware of the ways that plants contribute to our modern medicines, pesticides, poisons, perfumes, the flavouring of our dishes, and of course, our most popular beverages.

Personally, I’m not much of a coffee drinker, but it cannot be denied that coffee beans have had a profound impact on human history, and continue to today. It is estimated that there are “1 billion to 2 billion daily partakers” (p. 146) in coffee drinking, and this coffee drinking may have “helped pave the way for both the Age of Enlightenment and the Industrial Revolution” (p. 150), by spawning “revolutionary thinking” both directly and indirectly. Directly, through the stimulation it provided (in great contrast to alcohol), and indirectly, through bringing like-minded, intellectual thinkers together in coffeehouses. Still today we see this trend in our “Information Age”, with the mainstream love of coffee that has developed in office workers, university goers, and technology developers at large corporations.

I find it fascinating that humans are not the only creatures lured by the stimulating effects of caffeine. In fact, Hanson describes how caffeine is used both as a repellant AND an attractant in coffee plants. Caffeine produced in its leaves and beans wards off pests such as snails, slugs and beetles, as well as releasing an herbicide that rids of nearby competing plants, while caffeine produced in smaller amounts in the nectar of the plant’s flowers keeps bees coming back for another reinforcing hit of energy. These busy bees sound an awful lot like “morning commuters [lined up] at their favorite espresso stand” (p. 149). Hmm, another way in which we’re a lot more similar to bees than we may care to recognize. 😉

Throughout these four chapters, about diversified topics of rodents gnawing seeds, the spice trade, coffee, and the Cold War assassination of Georgi Markov using ricin (a violent poison derived from castor beans), Hanson does a wonderful job of stringing them together in a relevant way. He does this using the common thread of his work with the almendro tree. In Chapter 11, I came to learn that the almendro’s seed pods are not something so foreign or unheard of as I once thought – they are tonka beans, once commonly used as a vanilla substitute, and which remind me of a “tonka vanilla”-scented candle I once had. Even more interestingly, Hanson explains that tonka beans contain a potent active ingredient – coumarin – so potent that its derivatives are used to make rat poisons, and a blood thinning medication used in conjunction with chemotherapy.

Why some of these plants have evolved to contain such harsh toxins is in some cases still a mystery being slowly revealed, yet it makes me conscious of one thing: the importance of respecting plants, in their infinite abilities to both harm us and heal us.


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