The fossil of the world's oldest flowering plant (left) with an illustration of what it might have looked like some 174 million years ago (right).

Dinosaurs that lived during the early Jurassic period could stop and smell the flowers if they so desired, according to a new study that describes the oldest fossil flower on record.

The flower, named Nanjinganthus dendrostyla, lived more than 174 million years ago, the researchers said. Until now, the oldest widely accepted evidence of a flowering plant, also known as an angiosperm, dated to the Cretaceous period, roughly 130 million years ago. Meanwhile, a study using a computer model estimated that flowers evolved about 140 million years ago.

"Researchers were not certain where and how flowers came into existence, because it seems that many flowers just popped up in the Cretaceous from nowhere," study lead author Qiang Fu, an associate research professor at the Nanjing Institute of Geology and Paleontology in China, said in a statement. "Studying fossil flowers, especially those from earlier geologic periods, is the only reliable way to get an answer to these questions." [Photos: Ancient Flowering Plant May Have Lived with Dinosaurs]

To describe the ancient flower, Fu and his colleagues examined 264 specimens from 198 individual flowers that were preserved in rock slabs. These slabs came from the South Xiangshan Formation, a rocky area in China's Nanjing region that contains fossils from the early Jurassic period. The researchers found many detailed fossil specimens of the flower, which they then analyzed with high-powered microscopes.

This fossil shows a profile of a flower, including its ovary (bottom center), sepals and petals (on either side), and tree-shaped style (top). (Image credit: Fu et al., 2018/CC BY 4.0 license)

The flower had spoon-shaped petals and a stalky style that rose out of its center, according to the fossils.

One key feature of angiosperms comes in the "angio-ovuly," or fully enclosed ovules — precursors of seeds, which appear before pollination occurs. The newly discovered N. dendrostyla has a cup-like receptacle and an ovarian roof that come together to enclose the ovules and seeds. This structure confirms that the newfound plant was an angiosperm, the researchers said.

Some of the researchers on the study also took part in a 2015 study about a 160-million-year-old flower, Live Science previously reported. However, that specimen, dubbed Euanthus panii, is controversial because it was found by an amateur fossil collector in China and its age is uncertain.

A siltstone slab with Nanjinganthus fossils. (Image credit: NIGPAS)

As for N. dendrostyla, the researchers said they hope it will shed light on the early family tree of flowers. The scientists are still trying to figure out whether N. dendrostyla is monophyletic, which would mean it's part of an early angiosperm group that gave rise to later flower species, or polyphyletic, which would mean it's an evolutionary dead end that has little to do with flowers that sprouted after it.

"The origin of angiosperms has long been an academic headache for many botanists," study senior author Xin Wang, a research professor at the Nanjing Institute of Geology and Paleontology, said in the statement. "Our discovery has moved the botany field forward and will allow a better understanding of angiosperms, which in turn will enhance our ability to efficiently use and look after our planet's plant-based resources."

The study was published online yesterday (Dec. 18) in the journal eLife.

Originally published on Live Science.