New light shed on Charles Darwin's 'abominable mystery'

Darwin coined the phrase, abominable mystery, in 1879. In a letter to his closest friend, botanist and explorer Dr Joseph Hooker, he wrote: "The rapid development as far as we can judge of all the higher plants within recent geological times is an abominable mystery."

The mystery centres on the rise of the flowering plants, or angiosperms, the family of plants that produce flowers and bear their seeds in fruits. They make up the vast majority of all known living plants, from oaks to wildflowers and water lilies.

Flowering plants appeared on Earth relatively recently on a geological timescale, then swiftly diversified in an explosion of colour, shape and form. "In the fossil record they appear very suddenly in the Cretaceous, dated at about 100 million years ago, and there's nothing that looks like an angiosperm before them and then they suddenly appear and in considerable diversity," says Prof Buggs.

Questions raised by the sudden appearance of flowering plants are at the heart of Darwin's abominable mystery, he explains. "Why isn't there a gradual evolution of the angiosperms? Why can't we see intermediate forms between the gymnosperms - things like conifers - and the flowering plants? And why, when they appear, are they already so diverse?"