Charles Darwin's frustration with the evolutionary origin of flowering plants--he called it "an abominable mystery"--stood for more than a century, as hypotheses, like flowers, bloomed and faded. Botanists even argued over whether ancestors of the 250,000 flowering plants, or angiosperms, were tender herbs or woody, like shrubs. Now they may be writing the final chapters of Darwin's whodunit, not with the traditional phrases of fossils and plant anatomy, but with the letters and words of gene sequences.
Botanists have been particularly eager to learn more about the lowest branches of the angiosperm evolutionary tree--the plants that, having diverged first, are closest to the group's progenitors. But "as recently as the beginning of this year, people were viewing this as a difficult problem that might be intractable," says Douglas Soltis of the School of Biological Sciences at Washington State University in Pullman. Now, "within the space of a few months,...