Horsetail: Annularia stellata (PRI T-1762)

3D Model

Fossil foliage of the horsetail (Equisetophyte) Annularia stellata preserved in a concretion from the Pennsylvanian of the Mazon Creek area of northeastern Illinois (PRI T-1762). Note the whorls of leaves around the branch. Annularia is one of the foliage taxa for extinct, tree-size horsetails (Calamitaceae). Specimen is from the teaching collection of the Paleontological Research Institution, Ithaca, New York. Length of surrounding rock is approximately 15 cm. Model by Emily Hauf.