Have Seeds, Will Travel -- September 2010
With the passing of summer’s long days, brilliant greens and showy flowers comes the season of soft browns, modest asters and the tiny world of seeds. On the surface, the world seems to be slowing down. Yet a careful look reveals a great deal of activity in both the animal and plant worlds. As animals scurry to set their stores for the winter, plants too are working to insure the survival of future generations. The abundance of seeds this season provides a valuable opportunity for families to mark the amazing life cycle of flowering plants.
Each plant, of either field or forest, must find a way to disperse their seeds for a long winter’s sleep before the ground soon freezes. The methods used are as varied as the amazing diversity of plants they come from. From the spinning helicopters of sugar maples to the tasty clusters of raspberries, every plant has its own way to send its seeds around. This is the only time that plants can move, finding precious new ground for growth. Each seed is a new chance for the next generation.
The most common methods of seed dispersal can be summed up as either by mechanical means, wind or animals. There are variations within each of these broad categories, of course. For example, among the plants that use mechanical means there are “catapults” and “exploders.” While some plants, such as the tall stalks of mullein and the low lying common plantain, catapult their seeds when they are lightly brushed against, others, like the demure violet and colorful jewelweed, throw their seeds with a “pop.”
Seeds that are dispersed on the breeze also vary widely, from the helicopters of ashes and maples to the downy parachutes of dandelions. Basswood and linden trees have leaf-like sails that float whole clusters of berries to the ground. Milkweed perhaps has the most resplendent and silky parachutes, but lots of other flowers like thistle, goldenrod and asters also travel through the air.
Animals are helpful in a number of ways, beyond catapulting the seeds of mullein and plantain. Many seeds are wrapped up in a delicious layer of fruit, and actually rely on passing through the digestive tract of bears or birds or other animals before they can germinate. These seeds, like blueberries, raspberries, serviceberries and partridge berries, also benefit from the fertilizer they are deposited on the ground with. Acorns, walnuts, and other nuts are typically buried by animals, like squirrels and chipmunks, which store them for the winter. Some of these seeds are forgotten, and develop into new trees far from their parent tree. Perhaps the most ingenious use of animals is by seeds that “hitchhike” on their fur with tiny hooks, like burdock and beggar’s tick. These plants have even been known to hitch a ride on the clothes of unsuspecting humans.
Looking for seeds this time of year can be a rewarding new way to explore the local woods or fields you may already frequent with your family. It will encourage you and your children to get down on your hands and knees, look closely and tease apart dried flower heads and pods. A magnifying lens will come in handy when you find really tiny ones. Start a collection and make guesses about how the seeds may travel. Sort the seeds by their dispersal methods and glue them to a piece of paper. You will be sure to have a new appreciation for these tiny time capsules, the wandering future of familiar plants around you.