This time of year, PEI’s wildflowers are busy dispersing their seeds and they’ve come up with many ingenious ways to do this. I've showed you how Spotted Touch-me-not (Impatiens capensis) uses tiny springs to explosively propel its seeds from the pods (https://www.pei-untamed.com/post/spotted-touch-me-not). Today, I introduce you to a plant that uses animals to spread its seeds, whether the animals want to or not!
I’m sure you’re familiar with the prickly, sticky seed pods of Burdock (Arctium minus), but it is by no means the only plant that’s found success with this approach. I don’t have much Burdock on my property (because I regularly dig up first-year plants to eat the tasty roots), but my dogs make up for this by finding every local patch of Woodland Agrimony (Agrimonia striata), as Cuan demonstrates (Photo 1).
Agrimony is a member of the Rose Family (Rosaceae), and has a tall spike of small, five-petalled yellow flowers in summer (Photo 2). This plant is popular with pollinators, and I’ve seen Agrimony spikes bent over from the weight of our native bees on the flowers. Agrimony is native and common on the Island but easily overlooked, always seeming to blend in among other plants. You may not have noticed the flower, but if there is Agrimony in your area, I’m betting you’ve found its seeds!
In late summer and early fall, each of those yellow flowers turns into a bell-shaped fruit with hooked bristles surrounding the seed (Photo 3). This is an extremely effective seed dispersal unit that will cling tightly to any hair, clothing, or animal fur that touches it. From the plant’s point of view, the animal is helping by moving the seeds away from the parent plants and into new areas to colonize. From the animal’s point of view, those hooked barbs are mildly annoying as they work their way to the skin, ensuring the animal will groom them out of its fur. Humans also typically pull off and toss the seeds as soon as we notice them stuck our clothes. Agrimony seeds that stayed stuck wouldn’t have a chance to become new plants.
I’m fascinated by plant adaptations, in particular the many ways they use animals. We often look at plants from a human point of view, thinking flowers, fruit, and bioactive chemicals are just for decoration, food, and medicine. But plants don’t produce these parts to please our eyes, fill our stomachs, or cure what ails us; they’re strictly about survival and reproduction. Over the fall, I’ll show you some other cool plant adaptations that are part of PEI untamed!
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