Blue berries without blue pigment

Marble berries (Pollia condensata) look metallic blue, but no blue pigment makes that colour. Their gleam comes from microscopic structures in their cell walls: layers of cellulose arranged in a twisting stack selectively reflect light, producing the brilliant colour. Under a microscope, the fruit appears as a mosaic of differently coloured cells. Specimens collected in the 19th century were still colourful and shiny. The fruit can dry out while its colour-making structure survives.

1/3