Curr. Biol. 18, 1508–1513 (2008)

Credit: T. J. BARKMAN

The world's largest flowers, of the Southeast Asian Rafflesia genus, which mimic the smell and appearance of rotting flesh, evolved much more quickly and more often than botanists expected.

Todd Barkman of Western Michigan University in Kalamazoo and his team hypothesized that it would have taken a long time for the Rafflesia flowers to evolve from their smaller ancestors to their current maximum size of one metre in diameter because of the many structural and physiological changes required to support such large flowers. To their surprise, they found that the flowers of some Rafflesia species have more or less doubled in size during the past one million to two million years. As Barkman points out, it is hard to imagine a giraffe doubling the length of its neck in the same time frame. The scientists suggest that even bigger flowers could evolve in future.