A new species of monkey flower has been found growing on the banks of a stream in Scotland. But it is no ordinary discovery—the flower is a rare hybrid of two foreign species, and a glimpse into evolution in action. While just about all hybrids of different species are sterile—think of the mule, a sterile hybrid of donkeys & horses—this monkey flower is fertile, thanks to an unusual genetic duplication.
Quietly trailing the soil with slender stems, Mimosa pudica is an unassuming herb. While it does not invite attention, it responds dramatically to the touch. At a light caress, its fern-like leaves will fold inward; a gentle thrust will collapse the petiole. Mimosa pudica (Bashful Plant) is the introvert of the garden, yet, with a coy choreography that is curiously beautiful, it is impossible not to touch, and has fascinated botanists for centuries.
A blossoming buttercup begins with a seed, but that is an abbreviated version of the longer narrative: the evolution of flowering plants. Angiosperms would come to dominate the plant world with more than 250,000 species—a fantastic diversification that supported the evolution of insects and animals—but what of the first flower's origin? Darwin called it an "abominable mystery," and paleobotanists since have been similarly baffled by their sudden appearance in the fossil record.