Crinoids are an ancient group of fossils that first emerged in the Middle Cambrian period, about 300 million years before dinosaurs roamed the earth. Apparently they are a near perfect life form, because they still live in our oceans today.
Crinoids are attached to the sea floor with a stem-like appendage in their juvenile state, making them look plant-like, and for this reason they are sometimes called sea-lilies. There are some cool videos available of their modern descendants, often called feather stars, swimming. I highly recommend checking them out.
This limestone fossil of a juvenile crinoid is quite lovely. It will make a fine substitute for living flowers tucked by your books on oceans and paleontology.