About 70 species exist worldwide, mostly native to northern temperate and alpine regions of North America, Europe and Asia. They display colorful flowers — purple, blue, lavender, red, pink, yellow, or white. In addition, these flowers show an impressive spur, up to six inches (15 cm)-long in some species, directed backwards and secreting nectar.
These flowers have five-fold symmetry. Five tubular honey-leaves are semi erect with a flat limb and spurred or saccate at the base — saccate flowers have their basal coralla area extended and swollen, like a bag. The corolla is fused into a tube. The distinctive bulge appears on the lower side of the flower. Stamens are numerous (often more than 50) in whorls of 5. There are ten membranaceous intrastaminal scales. There are five pistils and the
carpels are free. The spur is directed backwards and secretes nectar.
Aquilegia originated in the upper Miocene ca.6.9 million years ago (Ma) in Eastern Asia. Diversification occurred 4.8 Ma with the split of two branches, one colonizing North America and the other colonizing Western Eurasia through the mountains of Central Asia. 70 species thus arising from a single ancestor raise the question of the mechanism. Botanists name adaptive radiation such a diversification from a single ancestor into multiple new
forms adapted to a variety of locations and conditions.
Adaptive radiation results from whole genome duplication, a characteristic feature in the evolutionary history of plants. All flowering plants are descended from a polyploid ancestor, which in turn goes back to an even older genome shared by all seed plants. Polyploid? Polyploidy is possession of more than two copies of each chromosome in the nucleus of a
cell. Repeated cycles of polyploidy radically restructure plant genomes. The nectar spur in columbine flowers exemplifies the adaptability of the genus. Eurasian and North American species show shorter, curved spurs, blue to purple in color. As a rule, bees effect their pollination. In North America, convergent evolution produced species with red and yellow
flowers, showing straight, medium-length nectar spurs primarily pollinated by hummingbirds. Other North American lineages with yellow or white flowers evolved long nectar spurs and are pollinated by hawk moths. In addition to these three pollination schemes, a species native to montaneous regions of central China, Aquilegia ecalcarata, has lost nectar spurs and is
primarily pollinated by syrphid flies.
Indeed, pollinators go for colors tuned to their eyesights. For instance, the bumblebee genus Bombus shows a strong preference for flowers with blue-purple colors. Birds show a preference for pollinating red flowers, while flies have a preference for yellow flowers.
Are humans that different? Clothing designers, with their Pantone charts, opt for fashionable colors years in advance. There are many fashion designers, a few prophetically lucky, most off-target as luck has it. As a rule, sports clothes display yet more brilliant colors. They have to show, for instance, against the backgrounds of ski slopes or of remote mountaineering areas.
In both cases, plants attracting their pollinators, young persons intent upon meeting a suitable date, driving forces of aesthetic satisfaction and of sexual reproduction are similar.