Thanks for the additional pictures @joseph-dumont! That helped clarify a few things for me. I checked both the collections here at the Florida Museum and the Paleobiology Database and did not find anything on fruits and seeds from the Brule of Nebraska. The PBDB did have an occurrence of Celtis (commonly known as sugarberry or hackberry) from the Brule of South Dakota though. Celtis is relatively common in the fossil record because it is one of the few calcifying plants and actually produces a mineralized endocarp. However, your fossil is not sculptured the same way a Celtis endocarp is. With the new photos I can now see that what I thought was a campylotropous condition is actually a deformity of the fruit. While I’m not 100% sure, if I had to put a genus to your fossil I would say it is a Prunus endocarp. This is the cherry genus but also includes things like apricots, almonds, peaches and plums. Prunus dates back to the mid-Eocene from southern British Columbia so the timing would fit well too. Thanks again for the share! Great find!