The East London Garden Society

Calceolaria Uniflora

Calceolaria Uniflora

Along the craggy peaks of the Andes from Chile into Argentina and down into Patagonia grows a strange alpine plant known scientifically as Calceolaria Uniflora. It goes by the common name of Darwin’s Slipper as its discovery is often attributed to Charles Darwin. However, this plant was first collected by French naturalist Philibert Commerson in 1767, 42 years before Darwin was even born.

Regardless, Calceolaria Uniflora is a remarkable little plant. It stands as an ornate example of a unique pollination syndrome, one that that is quite apt considering who discovered it. As with any strange flower, once you begin to ponder the significance of its morphology, you inevitably come to the same question; what on earth pollinates it?

The genus Calceolaria is bee pollinated. Relying on what are known as ‘oil bees’, most of the flowers in this genus produce hairs that secret oils which the female bees relish. Calceolaria Uniflora is different from the rest in that it doesn’t bother with oil production. Instead of producing flowers with a tube or a pouch, this species creates an almost alien‐looking red and orange bloom with a bright white appendage on its lower lip. So, what is going on there? The answer to this strange riddle has a clue in where this species grows.

At high altitudes, oil‐collecting bees are scarce. It is simply too cold and harsh for many insects to survive at such elevations. Instead, what are present are birds, specifically a species of seed‐snipe. These little birds exist on a plant‐based diet and spend a lot of their time holding territories and grazing on seeds and fruits of a handful of alpine plants. Researchers noticed that patches of Calceolaria Uniflora growing around these birds seemed to have high levels of floral damage, specifically on the lower lip where the white appendage is located. In fact, the white appendage was often completely removed.