[Pollia condensata is] a tropical metre-tall herb that sprouts its shiny berry-like fruits in clusters up to 40-strong. These little orbs are iridescent – they use special layers of cells, arranged just so, to reflect colours with extraordinary intensity. This trick relies on the microscopic physical structures of the cells, rather than on any chemical pigments. Indeed, the fruits have no blue pigment at all.
In the animal kingdom, such tricks are commonplace – you can see them at work on the wings of a butterfly, the shells of jewel beetles, or the feathers of pigeons, starlings, birds or paradise and even some dinosaurs. But in the plant world, pigments dominate and structural colours were thought to be non-existent.
Many animals use such structures to produce colour. This is why, like Pollia fruits, the wings of many butterflies and the feathers of many birds, can still look stunning after years in a fusty museum drawer. By finding the same structures in Pollia, Vignolini has uncovered a great example of convergent evolution, where species from different branches of the tree of life arrive at the same adaptations independently.
But Pollia fruits reflect more light than any bird or butterfly. Vignolini hasn’t just found the first strong iridescent colours in a plant; she’s found the strongest iridescent colours in nature. Or alternatively: “Ooh, SHINY!”