Whatever Happened to Cheilanthes horridula and Cheilanthes leindheimeri in Oklahoma

Oklahoma is where several ferns reach their northern or eastern range limits. Among them are two species of lip ferns in the family Pteridaceae, Cheilanthes horridula Maxon and Cheilanthes lindheimeri Hook (Hoagland et al. 2007). C. horridula (prickly lip fern) is primarily found on dry limestone slopes in the Chihuahuan Desert region of northeastern Mexico. Its range extends northward to southwestern Oklahoma. C. lindheimeri Hook (fairy swords) is widespread in central and northern Mexico as well as the southwestern United States (Mickel and Smith 2004). In Oklahoma, the distributions of both are limited, and the numbers of individual plants of each species are likely to be relatively small, compared with other Oklahoma members of the genus Cheilanthes.