I recall fondly the summer Imogene and I spent in Colorado with some fishing for trout and with much searching for and identifying Rocky Mountain wildflowers. We reveled in the beauty of both fish and flowers — gaining 80 different species of wildflowers before the new academic year beckoned us back to our faculty chairs at the university of our allegiance in Ohio!

That summer was a bit cooler and rainier than usual, great for flowers. The deep lavender-fuchsia petals of the mountain penstemon flowers along a trail high above the old mining town of St. Elmo seemed almost to drip pigment. The dog-toothed violets, with their brilliant yellow curved petals, were found on the tailings of a long-abandoned mine so high and remote that we had to rent a 4-wheel-drive, off-the-road vehicle to reach them. The search for beauty always is money well spent, i.e., if we take time to absorb some of the radiance and not just use the sighting to check off some item on a list.

The connection between humans and flower blossoms goes beyond romantic, approaching the mystical with the way flowers decorate our tables, porches, lawns, gardens, caskets … and our hearts. Some human occasions simply are not complete without the presence of certain brilliantly-colored floral participants.

Flowering plants have a long and storied biological history, with the most recent ancestor of all living flowering plants having appeared in the fossil record some 130-plus million years ago. This ancestral form has since diversified into 300-350 thousand species, making up a major percentage of present-day plant species. They and their pollinators (especially insects) have co-evolved together from the beginning. Some pollinations occur via wind, some by humming-birds and bats, but most by some species of insect — mostly butterflies, moths, bees and wasps.

Before launching into that story of co-evolution, it would be well to recall a basic process that powers evolution (or “descent with modification,” the name Darwin used). Many members of a new generation of organisms — all of the robins that will hatch in NE Kansas during 2025, for example — will have experienced one or more genetic mutations during early development that caused them to be different (having variations in their anatomy, or physiology, or biochemistry, or behavior) from their generation-mates. These variations most usually are small, not obvious from casual observation, and usually will have little or no positive or adverse effect on the individuals bearing them. 

However, in times of ecological disturbance, one or more of these variations may prove useful in allowing the bearer of that variation to survive and pass its genes into the next generation—an important measure of evolutionary success.  For example, let’s take a lone male desert cottontail rabbit in the desert cottontail population on a large sagebrush slope in New Mexico. In a severe drought, the variation in question allows this single rabbit to survive a loss of body water beyond that of any other male rabbit on that slope. Come next spring, only that male rabbit from his generation on that sagebrush slope is alive to pass his genes into the next generation of desert cottontails on that slope. Perhaps this “water-tolerance” trait will breed true and enable the recipient rabbits to retain that ability: a new ability with which to survive future times of drought.

Or, in the co-evolution story to be considered, perhaps one variation seen in a generation of a particular flower species is that some of the generation-mate flowers have a longer-than-usual flower tube with the nectar lying deeper. If one or more of the new generation of a certain hummingbird species has a longer-than-usual bill and tongue, said bird could perhaps reach the nectar at the bottom of the longer tube. A new relationship is born! If additional variations in this relationship occur, it may lead to sufficient differences in a group of the particular flowers or in that hummingbird species, that a new variety — even a new species — may emerge. This sort of thing seems to have happened “all over the place,” over the hundreds of millions of years of life on Earth.

This co-evolution of flowering plants and insects is one of nature’s most striking examples of adaptation, specialization, and of symbiosis: where both species in the relationship benefit from the interactions. Flowering plants have developed many different colors, scents, and anatomies (unknowingly) that attract a pollinator. Insects, with the tiny variations of anatomy, physiology, chemistry, or behavior seen in each generation, have offered variations that have been able to supply the pollination needs of most flowering plant species.

In some cases, the mechanics of co-evolution have developed to an extreme degree. Consider the genus of fig trees — over 800 species. Each fig species has a corresponding species of fig wasp that pollinates only that species of fig tree. This may sound great on one level, but specialization in nature is flirting with extinction. If one of the fig moths would somehow become extinct, extinction for its fig tree might not be far behind. The lovable koala of Australia has a very specialized diet: only eucalyptus tree leaves. Just imagine if all of this type of tree suddenly died off.

The family of orchids holds great examples of specializations of both flowers and insects to achieve pollination and nectar gathering. Some species have evolved shapes, which are challenging for a pollinator or nectar-gatherer. Mutations in insect anatomy seems to have answered the call. One of the most famous stories involves what is known as Darwin’s orchid, also known as the Madagascar star orchid, Jerusalem star orchid, or the star of Bethlehem orchid. This beautiful star-shaped flower has a very long, deep flower tube, sometimes as long as eleven inches. Darwin received a sample of this orchid in 1862, and he soon argued that the flower was pollinated by a not-yet-discovered species of sphinx moth with a long proboscis. This moth was discovered 41 years later! Both evolution, and our attempts to understand this complicated and multi-faceted process take time, sometimes eons of time.