And what a specimen it is! The spectacularly preserved fruit was found in 2018 and measures 6-1/2" round. Here you can see both the part and counterpart in fine detail. Doug Miller of Green River Stone sent copies to me this morning and a copy to the deeply awesome Kirk Johnson, resident paleontologist over at the Smithsonian Institute, to confirm the ID.
There is another spectacular specimen from Fossil Butte National Monument. They shared photos of a Nelumbo just yesterday. Nelumbo is a genus of aquatic plants in the order Proteales found living in freshwater ponds. You'll recognize them as the emblem of India, Vietnam and many wellness centres.
Interestingly, these lovelies can thermoregulate, producing heat. Nelumbo use the alternative oxidase pathway (AOX) to exchange electrons. Instead of using the typical cytochrome complex pathway most plants use to power mitochondria, they instead use their cyanide-resistant alternative. This is perhaps to generate a wee bit more scent in their blooms and attract more pollinators. The use of this thermogenic feature would have also allowed thermo-sensitive pollinators to seek out the plants at night and possibly use the cover of darkness to linger and mate.
So they functioned a bit little like a romantic evening meeting spot for lovers and a wee bit like the scent diffuser in your home. This lovely has an old lineage with fossil species in Eurasia and North America going back to the Cretaceous and represented in the Paleogene and Neogene. Photo: Doug Miller of Green River Stone / Lotus Image: Sarah-Anne Juliette McCarthy / Foliage Image: J.M.Garg - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=7249919