Co-Evolution: The Story of Flowers
Today's class included all my favorite things - gardens, flowers, pollinators, and co-evolution!
We started off sharing developments from our home gardens. Everyone noted how early spring crops are ripe for harvesting, including peas, beans and potatoes. Some gardens have ripe tomatoes, while others (mine included!) are still waiting for fruit.
One thing I've noticed around my gardens is the recent bloom of all my day lilies. These simple blossoms present the perfect opportunity to dissect and study flower anatomy.
Flowers we picked apart in class today: daylilies, sweet peas, scarlet beans, allium, nasturtium and a rosehip fruit!
Why spend time studying a flower? Plants are the key to life on earth, making their energy from sunlight and providing food to other life forms. Flowering plants tell the story of co-evolution with pollinators, such as bees, butterflies, moths and birds. The arrangement of a flower’s sexual structures and the timing of their emergence all correspond with the life of another species. Both plant and pollinator benefit from the other. Understanding this symbiotic relationship is fundamental to understanding all of Earth’s ecosystems, humanity’s food systems, and the microcosmic balance of our own gardens.
We proceeded to explore our flowers, playfully pulling them apart like children and then examining them like botanists. We learned about the reproductive structures that most flowering plants have in common, and hunted for them in a variety of blooms. Most flowers have male and female reproductive organs, the male being the stamen that produces pollen, and the female being the stigma that receives pollen. The appearance of these structures varies greatly between flowers, making them sometimes tricky to identify. We noted how different flowers attract different sorts of pollinators, usually inviting bees and other insects into the center of the flower to brush up against anthers full of pollen, and to then deposit it on another flower's stigma. This cross pollination is essential to the genetic diversity of plant populations.
The better we understand how plants live and reproduce, the better we understand their roles within ecosystems. A book that guided my plant study as an adolescent still holds up today as a perfect introductory guide to botany, or the study of plants: the Eyewitness Book of Plants. I recommend getting a copy to anyone who enjoyed class today. You can buy a used copy here.
Challenge for next time:
At the end of class, I invited everyone to find a flower in their yard, and to try to identify the structures we looked at in class today: sepals, petals, stamens, anthers, and stigma. What sort of pollinator is likely to visit this flower? How do its colors, shapes, scents and reproductive structures invite a pollinator in? Is the flower a long tube that would require the long tongue or proboscis of a hummingbird or butterfly, such as a honeysuckle or bee balm flower? Is there so much pollen on the anthers that your finger picks it up by brushing against them like a bumblebee?
I also invite you to spend time in your garden observing what types of pollinators choose to visit certain flowers. This requires some patience and attention. Noticing flower/pollinator pairs would be a great subject of study for your nature journals!
