Fossil specimen of the horsetail *Asterophyllites* sp. from the Pennsylvanian Tonganoxie Sandstone of Franklin County, Kansas (PRI 50619). Note the whorls of leaves around the branches. *Asterophyllites* is one of the foliage taxa for extinct, tree-size horsetails (Calamitaceae). Specimen is on display at the [Museum of the Earth](http://www.priweb.org), Ithaca, New York. Length of specimen is approximately 16.5 cm. Model by Emily Hauf.