For all that Charles Darwin figured out about life on earth, he was perpetually perplexed by flowering plants, calling their explosive evolution an “abominable mystery.” Now, a newly analyzed fossil species has shed light on where these plants, known as angiosperms, may have gotten their start. In water is the surprising suggestion.

For years botanists thought that angiosperms, which came to dominate the terrestrial landscape 160 million years ago, had arisen on dry land as they evolved from existing land plants. Bolstering the idea was the discovery in 1999 that a tiny land-dwelling shrub called Amborella sits at the base of the angiosperm family tree. “The consensus is that [flowering plants] originated on land and moved into water,” says Michael Donoghue, an evolutionary biologist at Yale University. Read more.