The oldest known fossil of a flower bud has been discovered by researchers in China, pushing the evolution of flowers back in history by at least a couple dozen million years and changing the way we think about how brontosauruses celebrated Valentine’s Day.

“Many paleobotanists are surprised [by the fossil], as it is quite different from what is stated in books,” Xin Wang, of the Nanjing Institute of Geology and Paleontology, told Live Science. “But I am not so surprised.”

Wang is the senior author of a new paper on the discovery, published in the journal of the Geological Society of London.

The flower, named Florigerminis jurassica by the researchers who found it, is a type of angiosperm – that is, a flowering plant. The origins of angiosperms are the subject of some controversy in paleobiology: flowers are usually too fragile to survive for millions of years in the fossil record, so the evidence on their evolution is spotty.

Previously, they were only known to have existed as far back as the Cretaceous period between 66 and 145 million years ago, but there are a few fossils that have turned up over the past few decades that have hinted at an earlier origin.

One of those fossils – an ancient Nanjinganthus dendrostyla whose discovery was the subject of a 2018 paper published in eLife – is even older than F. jurassica. However, its status as a true flowering plant proved controversial: some researchers thought N. dendrostyla was not complex enough to count as an angiosperm, while others argued it was too complex to be a non-flowering plant (or “gymnosperm”).

1. F. jurassica, though, “includes not only a leafy branch but also physically connected fruit and flower bud,” Wang explained in a statement. That removes all ambiguity: if one plant can have a flower bud and a mature fruit, the team said, then it implies the existence of blooming flowers in the in-between stage.
3. The researchers hope that their new discovery will trigger a rethink on the origins of flowering plants – and maybe even the induction of those Jurassic “gymnosperm” fossils like N. dendrostyla into the angiosperm club. Until now, Wang told Live Science, many plants which could potentially be angiosperms were assumed to be gymnosperms simply because they were from the Jurassic.

“We hope that the discovery of [F. jurassica], with its branch, leaf scars, flower bud and physically connected fruit, may help to ease the pain of accepting pre-Cretaceous angiosperms,” the authors conclude in their paper. “The currently accepted theory of angiosperm evolution needs to be revised.”