We all love flowers right? Certainly, some make us sneeze, some don’t appeal to our sense of smell, still others aren’t very showy and don’t catch our attention, yet generally, we appreciate them. That said, despite this appreciation, in my never-ending quest to inform the Capitol Hill populace about the natural world mingling with our city streets, I’ll hazard that many of us don’t truly understand flowers.
Why do we like flowers anyway? This is not a simple question for the likes of a short column, but there are several broad explanations. Occam’s Razor, the concept that the simplest explanation is often the best, could lead us to understanding that we appreciate flowers simply because they are beautiful and represent fertility. From a biologist’s point of view, one might say humans appreciate flowers because in deep evolutionary time, our ancestors saw that flowers meant fruit and therefore sustenance. People have been tending angiosperms (flowering plants) for thousands of years and before agriculture certainly paid close attention to what plants bore edible fruit after flowering.
Having figured out that flowers mean food, we worked to figure out how to best increase food production. This meant understanding flower anatomy, which I’ll briefly explain. While there are exceptions, a large majority of flowers we see in our gardens and parks are considered “complete flowers” containing male and female parts, effectively making each flower hermaphroditic. In a complete flower, stamens, collectively known as androecium (roughly translated from greek: the man’s house), consist of pollen producing anthers, which sit on the end of a filament. When a insect, bird, or mammal visits for a sweet sip of nectar (the reward for visiting a flower) pollen rubs off on them and they carry it off to the next flower. Pollen, where a flowering plant’s sperm comes from, need eggs to fertilize, which are found in the female portion of the plant, the Gynoecium (roughly: the woman’s house). Stamens of a complete flower circle around the female part of the flower, typically central, called the pistil. Pistils are sticky, taking in pollen, which eventually fertilize ovules (eggs) to produce fruit and in turn seeds.
We may think we are in control of the flowers we plant in our gardens, but in one view, we are actually being manipulated by them. After all, they’ve encourage us to plant them by simply smelling or looking nice thereby perpetuating their genes. These are often the same reasons pollinators visit them. The petals, what we often focus on in a flower, often showily announce to a bee or a hummingbird that they are open for business. Other plants merely give off an aroma that draws us near, or in other cases, like that of our native Skunk Cabbage, stink to high heavens to trick carrion eating insects into visiting. Bottom line is that a large majority of the flowers we see every day rely on pollinators, just as the pollinators rely on the plants as a source of food. The new plan for an 11th Ave pollinator pathway should help.
Sit down anywhere with a few flowering plants right now and you’ll be astounded by the number of insects that are swarming them. In a more natural setting, we might expect to see certain insects on certain plants, as it’s not uncommon for insect and plant anatomy to match, even to the point of a flower restricting all but a few species from their nectar. Alas, Capitol Hill is largely no longer a place of specialization, but instead a world of generalists wrought by our introduction of exotic plants and animals.
That’s not to say that all native species do poorly in the face of our garden plants nor that we shouldn’t appreciate what we’ve got. We’d definitely do well to plant natives. For a good baseline of species look to the Central District’s pollinator pathway. But many insects are happy to visit dandelions as much as natives. The messages that bright flowers send to insects or other animals that might have never fed on them before are often the same or similar to native species (although sometimes the food isn’t quite as good). Bumblebees just happen to be one of the only effective pollinators of the tomatoes in our gardens, despite the plants not being native. Where evolutionarily old species have found extreme specialization, some have also found generalization to be adaptive.
Even in the small yards we often have in our dense neighborhood, there’s a good chance you’ll have some plants you hope will bear fruit. Espaliered fruit trees have become more and more common in our cramped quarters and their flowers being reproductive organs need help from pollinating insects. Apple or pear flowers that don’t get complete pollination produce lopsided, undersized fruit.
When I look at weedy clover flowers mixed into the lawn of Volunteer Park, I think less about human sustenance and more about the tremendous beauty and complexity of form and function they represent. Yet understanding flower anatomy and function may have seemed semantic till now, but they have real implications in our daily lives because we eat food that started as an unfertilized flower, even the meager portions of fruit we grow for fun on the margins. We don’t rely on all flowering plants for life, but we most certainly wouldn’t be around without them. That’s as good a reason as any to enjoy them this summer, from garden roses to the odd dandelion, as you go about your days on the Hill.
Previously in Pikes/Pines