I have long been fascinated by seeds, as my elementary school self with her shoebox full of horse-chestnuts (Aesculus hippocastanum) can attest. It turns out this fascination served me well when I became a graduate student. As part of my research on different methods to control downy brome (Bromus tectorum), I counted thousands and thousands of downy brome seeds to document the effects of those different methods. If you’ve ever wondered what a plant science graduate student does, you can bet that counting seeds is part of it.
As a kid, my fascination was purely aesthetical; the shiny, smooth, brown horse-chestnut appealed to my sense of touch and sight. As an adult, my sense of wonder at these packages of energy (because, really, that’s what they are) continues to grow.
The potential within a seed is astounding. It contains everything it needs to start life. Sometimes that start comes as soon as the seed drops to the ground and other times those seeds can be incredibly patient. Waiting tens, hundreds, or even thousands of years for the right conditions to germinate; in the case of field bindweed (Convolvulus arvensis) , the seeds of which can remain dormant for 40+ years, this is a real pain if you’re trying to keep your lawn and garden weed free. On the other hand, in the case of Methuselah, the Judean Date Palm grown from a 2,000 year old seed, that’s pretty darn amazing if you ask me.
Whether it’s the tiny speck-like seeds of an orchid or the large and cumbersome seeds of a coconut, all seeds start with the same basic components: a protective seed coat enclosing an embryo (the baby plant), endosperm (the “sack lunch” food supply), and cotyledons (the first leaves to emerge and get photosynthesis going). But that’s about where the similarities end; and where the fun (speaking as a plant nerd, here) begins. Plants, being the rather stationary creatures that they are, have developed a myriad of creative ways to get around – well, to get their seeds around.
Some, like dandelions (Taraxacum officinale)or milkweed (Asclepias sp.), have harnessed the power of the wind. Those feathery, floaty structures (the pappus) that are so fun to blow around weren’t created for our amusement alone, but rather to disperse their progeny. And though they all look similar at a glance, take a closer look next time and you’ll notice that the pappus is quite unique to each species; some are highly branched and delicate while others are more robust.
Others put their fate in the hands (or fur, or socks) of passing animals. Houndstongue (Cynoglossum officinale) and burdock (Arctium minus) are two such examples. If you’ve ever gone hiking and then had to spend a good while afterward pulling all the burs off your socks or out of your dog’s hair you probably haven’t had very kind feelings towards these plants. But they have proven themselves useful as well – burdock is where the idea for Velcro came from!
And of course I have to mention all those plants who package their seeds inside delicious fruit! We may think that those juicy tomatoes or crisp apples are designed to provide us with tasty and nourishing treats, but have you stopped to consider that maybe the plant is using us? Hoping that by tempting us with something to eat we will deposit their seeds in a new location to grow a new generation?
Regardless of whether we’re using the plants or the plants are using us, right now is a great time for seed observing (and collecting, and eating!).