Treetop flowers a springtime love story

May is a month full of energy, urgency, and drama. Robins duke it out on our lawns, frogs sing passionately for love, and fish spawn with abandon.

There's botanical drama in the treetops, too, but it goes largely unnoticed by earthbound passersby. You won't see it unless you've got balcony seats -- or really good opera glasses.

Let's take a look at this lesser known drama. The stars of the treetop show are flowers -- unobtrusive petal-less flowers way high in upper reaches of the forest canopy. There's a cast of thousands: oak flowers, walnut flowers, elm flowers, cottonwood flowers, maple flowers and more.

"Wait a minute!" you say. "Trees aren't wildflowers!"

No, but trees do indeed produce flowers. They are quieter than the spectacular spring flowers carpeting the forest floor. They are more subtle than the showy blooms of ornamentals like magnolia trees. They are modest compared to the gaudy bouquets of catalpas, and they lack the heavenly fragrance of apple blossoms.

Understated as they may be, the flowers of our forest trees are dramatic protagonists facing the age-old conflict of "boy must meet girl, but how?" There's an element of suspense in this drama: Will the handsome gent find his way through the forest to meet the fair maiden? Will he make survive the thunderous storm?

There's an occasional antagonist to thicken the plot: Will the bushy-tailed, tree-climbing herbivore gnaw off the branch and send the flowers crashing to their death? And of course there's some steamy sylvan romance when and if boy does meet girl.

The underlying theme of the drama is to get pollen from the male flower to the receptive parts of the female. This is accomplished in dozens of different ways throughout the plant kingdom.

Some tropical flowers have accomplices like bats to get the job of pollination done. The lowly skunk cabbage of our wet woodlands lures carrion flies to its foul-smelling flowers in order to transport its pollen. Other flowers enlist slugs, hummingbirds, ants, bees and a host of other creatures to play matchmaker. All these flowers attract their pollinating partners with alluring color patterns, nutritious nectar and/or sweet perfume.

In our treetop production the flowers have a different strategy altogether. The flowers are small, inconspicuous, and odorless. They have no petals, no perfume, no showy colors or tantalizing nectar. They have traded interdependence with animal pollinators for independence in pollination. They have literally abandoned themselves to the wind.

Wind pollination, or anemophily, is a risky strategy. What are the chances that a tiny pollen grain from a male flower on Tree A will ride the wind and successfully land on a receptive female flower on Tree B way across the ravine? What if the wind blows in the wrong direction? What if there's no wind? What if a torrential rain knocks the pollen to the ground? It's a huge gamble and the odds are slim.

So, like buying lots and lots of lottery tickets with the hope that one will be a winner, wind pollinated trees produce lots of male flowers with lots and lots of pollen. And to help increase the odds of success, wind pollinated female flowers have developed relatively large receptive structures to increase the chance of catching a pollen grain.

Take a look at the flowers of a maple tree. You won't have to climb a tree to find these, because many of them have fallen to the ground thanks to the aforementioned antagonist, the squirrel. See those long green string-like structures coming from clusters of cup-shaped bases? Those are the male flowers and the long "strings" are called stamens. At the ends of the stamens are the anthers. It's these little sons-of-guns that fire off millions of air-borne pollen grains, the bane of allergy-prone people down-wind.

The female flowers are harder to decipher. They are the paragon of simplicity, comprising structures called styles attached at a common base. At the end of each style is a receptive stigma where that one lucky pollen grain needs to land. The base of the styles is the ovary.

The odyssey of the pollen grain riding the precarious wind continues when -- and if -- it lands on one of the female stigmas. The pollen now faces the challenge of making its way down the style to the ovary. If it makes it -- applause, applause! -- a seed will develop and the ovary will ripen into a fruit.

In the case of the maple tree, the fruit becomes the two-seeded "helicopter" that twirls through the air. If the tree in question is an oak, an acorn will be born. Walnuts, hickory nuts, ash seeds and cottonwood fluff are all formed in this way from wind-pollinated flowers.

The plot can get complicated as the cast of characters may align themselves in numerous ways. Some wind-pollinated plants have separate, unisexual flowers on the same tree. Some species have separate, unisexual flowers on different trees -- in this case a tree may be referred to as a male tree or a female tree.

This is important to know if, for example, you have a cottonwood tree in your yard. Male cottonwood? No problem. Female cottonwood -- prepare yourselves for a snowstorm of white fluffy seeds coating your lawn, clogging up your screen door, and drifting into your porch!

However the story plays out, the pollen grain deserves a standing ovation. Then it will be the female's turn. Her grand finale will come next fall when a shower of acorns descends from the treetops, hickory nuts plop to the ground, and walnuts roll down the trail. Maybe a few seedlings will sprout from those nuts.

Just wait. The sequel is coming to a forest near you.

• Naturalist Valerie Blaine botanizes high and low throughout Kane County forest preserves. You may reach her at blainevalerie@kaneforest.com.