What would our world be like without flowering plants? Some 300,000 species of angiosperms are alive today. Their blooms color and scent our world; their fruits, roots, and seeds feed us; and their biomass provides clothing, building materials, and fuel. And yet this rapid spread and dominance of the terrestrial landscape, which took place perhaps 100 million years go, apparently happened in a blink of geological time, just a few tens of millions of years.
The father of evolution couldn’t quite fathom it. In 1879, Charles Darwin penned a letter to British botanist Joseph Dalton Hooker, lamenting an “abominable mystery” that threw a wrench into his theory of evolution: How did flowering plants diversify and spread so rapidly across the globe? Now, 130 years later, botanists are finally beginning to make sense of what has made this plant group so successful and are sorting out how, and when, flowers got started—and from which ancestor. April's Origins essay, "On the Origin of Flowering Plants," discusses how researchers now have analytical tools, fossils, genomic data, and insights that Darwin could never have imagined, all of which make these mysteries less abominable. Over the past 40 years, techniques for assessing the relationships of organisms have greatly improved, and gene sequences as well as morphology now help researchers sort out which angiosperms arose early and which arose late. New fossil finds and new ways to study them—with synchrotron radiation, for example—provide a better sense of the detailed anatomy of ancient plants. And researchers from various fields are figuring out genomic changes that might explain the amazing success of this rapidly evolving group. Questions still remain, particularly about the nature and identity of the angiosperm ancestor itself. But modern botanists are hopeful that the abominable mystery is well on its way to being solved.
Credit: Reproduced with the kind permission of the Director and the Board of Trustees, Royal Botanic Gardens, Kew