The Lundell Herbarium (LL) is part of the Billie L. Turner Plant Resources Center, which houses the combined herbaria of LL and the University of Texas Herbarium (TEX). The combined PRC collections include over one million specimens from all parts of the world. The two herbaria (TEX and LL) are completely integrated and interfiled, although each sheet is marked as to its herbarium and should be cited as such. The TEX Herbarium, with close to 700,000 specimens, dates to the 1890s and is especially strong in Texas and Mexican specimens. It has been associated with an active plant systematics graduate program for several decades, and the research interests of faculty, staff, and graduate students have led to strong representation of Asteraceae, Fabaceae, and Rhamnaceae, among other families, as well as the Chihuahuan Desert region (Mexico and the U.S.) and the mountains and plains of northeastern Mexico. The LL Herbarium, with ca. 320,000 accessions, represents the former personal herbarium of Cyrus Lundell and includes numerous Texas specimens as well as a strong concentration of flora from the Mayan region of southern Mexico and adjacent Central America. The LL herbarium also has good historical depth, with collections dating to the 1750s. However, it is no longer actively expanding; all new specimens received into the Plant Resources Center are now accessioned into TEX.