It’s in your nature: Seed dispersal
Maple trees produce samaras (helicopters) to disperse their seeds. These samaras are from red maples. BARRY REED/SPECIAL TO THE TIMES NEWS
Milkweed pods are green until “ripening.” They then invert, and the “parachute sails” carry the seeds with the wind.
Some trees, like this crabapple, produce tasty fruit to entice animals to eat them. Later, the seeds may “pass through” the birds and are deposited elsewhere with their droppings.
Common burdock uses mechanical means to spread its seeds. The multi-barbed fruits attach to animals’ fur (or your socks) to be dispersed.
A gray squirrel feasts on persimmons, pictured here, or acorns, caches them away for later use under leaf litter, and spreads the seeds sometimes a great distance from the parent tree.
After a fox pup is weaned and no longer fed by the parents, it is “forced” from the den area and begins its search for food and thus a new territory. If it encroaches into another predator’s territory it will continue to move on. If it finds a suitable habitat offering what it needs, that will be “home.” Mobility is a key to mammals’ and birds’ successes. In order to continue the species, it needs food, water and shelter.
Plants don’t have mobility. Plants need soil, water, nutrients and sunlight to survive. Like animals, to sustain the species, they must reproduce. The fox, if one of its necessities is no longer available, can move on to another location. However, a sycamore tree for example, gets its flowers pollinated, gets its seeds developed, but it cannot move about to find a better “home.” Or can they?
Sycamore trees prefer to grow near water courses, stream banks or lake shores. Its fruits, containing the seeds (its offspring), can float. Like a toad with thousands of eggs, trees produce an abundance of seeds, hoping that statistically, some will find a suitable place to grow. It will not survive in the shade of the “mother tree” where it won’t get enough sunlight, water or nutrients.
An oak tree can produce thousands of acorns, most of which are either eaten by jays, squirrels, turkeys or deer, or get cached away in the soil by well-prepared squirrels. Fortunately for oaks, some of the buried acorns get forgotten, and they are already planted. (If the acorn is buried under a tree or trees they may not get enough sunlight to be able to grow.
Wind is used by many plants to disperse the seeds. A maple tree has a winged fruit called a samara (helicopter) which allows the wind to carry them a considerable distance away from the branches. (Pine seeds blow out of a ripening pine cone in much the same way.) That explains how white pine seedlings begin growing in the middle of a field no longer mowed.
Two specialized plants of which you are familiar use sails or parachutes to carry the seeds. Milkweed produces a green seed pod, which when it ripens, inverts and the seeds with a white downy sail blow away. Dandelions use a similar technique. (This explains how your immaculate lawn hosts dandelions the following year (your neighbor upwind didn’t mind dandelions in their lawns.)
Some other herbaceous plants use mechanical means. Burdock fruits are like Velcro balls which stick to the fur of an animal after it brushes the plant. Hours (or miles) later, a fox sits down and grooms the matted fur, dropping the burdock seeds in a new territory. Stick tights, beggar’s ticks, and stick seed use the same method. You probably removed a group of small triangular seeds stuck to your socks and inadvertently dropped them in your backyard.
Apples, pears or autumn olive have produced tasty fruits which entice animals to eat them. Later, they regurgitate some seeds or “deposit the seeds with their dung,” fertilizing them as well. No matter the method, plants have successfully developed avenues to spread their seeds insuring the plants’ longevity.
Test your outdoor knowledge: ______ wrens can’t be seen in Pennsylvania. A. Winter, B. house, C. Carolina, D. marsh, E. all are found here.
Last week’s trivia answer: About 10 flycatcher species can be found locally.
Contact Barry Reed at firstname.lastname@example.org.