Fossil of the horsetail (equisetophyte) *Asterophyllites equisetiformis* from the Pennsylvanian of Franklin Co., Kansas (PRI 49838). 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 rock is approximately 9.5 cm. Model by Emily Hauf.