The Plant Resources Center (PRC) acquires, preserves, and makes available for study samples of plant biodiversity from Texas and other regions of the world. The center comprises two originally separate herbaria that are now housed and filed together, yet maintain their separate identities: The University of Texas Herbarium and the Lundell Herbarium. These collections of preserved vascular plant specimens provide a temporal and geographic record of plant diversity that is especially strong for Texas and Mexico, with general representation from most parts of the Western Hemisphere and lesser representation from other areas.
Visitors to the Center will find specimens of pressed and dried plants or plant fragments mounted on archival paper with a record of their identification, provenance, date of collection, collector, and often ecological and morphological information. These are housed in insect-proof cabinets and arranged by their relationships (that is, taxonomically). The PRC also has a collection of about 3,300 pollen samples permanently mounted on microscope slides, and a library with classical and modern literature on plant systematics (the science of plant classification and relationships).
The impetus for the PRC began in the 1890s with a collection of plants made by Fredrick W. Simonds, a professor of geology at The University of Texas. The first substantial growth of the collection was due to the efforts of Dr. Mary S. Young, who served as curator of the herbarium from 1912 until her death in 1919, during which time more than 13,000 specimens were added, including over 2,250 that she collected herself. A second significant period of expansion was led by Dr. Benjamin C. Tharp, who guided the herbarium from 1919 until the mid-1950s. During these years, the collection grew from 16,000 to 200,000 specimens, still with a strong concentration on Texas plants. In 1943, The University of Texas Herbarium was recognized as a separate administrative and fiscal unit within the university, and Dr. Tharp was named its first director. With Dr. Fred A. Barkley serving as curator from 1942 through 1947, active programs of plant collection were established in Mexico and duplicate specimen exchange with a variety of other herbaria.
Dr. Billie L. Turner assumed the directorship of the herbarium in 1958, marking a period of unprecedented organization and growth. With the combined efforts of Dr. Turner, Dr. Marshall C. Johnston, and their students, the number of specimens climbed to 300,000 by 1970, with Mexican samples a major part of the growth, establishing the collection as an indispensable resource for research at the university. Dr. Turner oversaw the relocation of the collection to its current home in the Main Building, and he expanded the scope of the herbarium to include the library and research activities. The establishment of the PRC in 1975 enabled Dr. Turner to attract the Lundell Herbarium collection to The University of Texas, which added a collection of 315,000 specimens with especially strong representation of Texas and northern Central America. This acquisition, completed in 1990 and combined with the 500,000 specimens of The University of Texas Herbarium, resulted in one of the most important herbaria in the United States.
Since 2000, the PRC has benefited from the directorship of Dr. Beryl B. Simpson, who has successfully led the effort to make available online a database of all the specimens from Texas. The collection continues to grow at a rate of about 10,000 specimens per year through additions from staff, students, and faculty, gifts, and exchange of duplicates with other herbaria. It now contains more than one million items.
The specimens in the PRC represent the efforts of hundreds of botanists since the nineteenth century, fanning out into the remote and at times barely accessible corners of Texas, Mexico, and the entire globe to collect and document the native flora of these regions. The samples represent both the raw data and the posterior documentation for hundreds of studies on plant classification and evolution (systematics), inventories (floristics), and plant utilization. They continue to serve as the data for present and future studies and an invaluable aid in the identification of recently collected plants. The collection also has an important historical aspect: some of the specimens are more than 200 years old, and over 600 specimens collected in central Texas between 1846 and 1851 by Ferdinand Lindheimer, the "Father of Texas Botany," form part of the PRC.
The strength of the collection lies in its depth and breadth of material from Texas, Mexico, and northern Central America. Botanists studying the systematics of any plant group or making an inventory of plant biodiversity in some part of this region would find the holdings of the PRC indispensable to their research. Across the spectrum of flowering plants, the PRC is strongest in the sunflower family (Asteraceae), with about 175,000 specimens. Other important holdings include the Myrsinaceae, Eriocaulaceae, Verbenaceae, and Celastraceae families. The collection also houses about 7,500 type specimens, which serve as the critical reference for the system of scientific names of plants.
The PRC collections are used by scientists, students, government agencies, and, most frequently, by scholars interested in plant systematics or floristics. While many researchers work directly in the collection, the PRC also lends specimens for research purposes to other institutions. The use of archived material has increased significantly as advances in molecular (DNA) techniques make the herbarium a prime tool in understanding the evolution of plants. Personnel of such state agencies as the Texas Department of Transportation and the Parks and Wildlife Department, as well as of conservation organizations such as the Nature Conservancy, routinely consult the collection to verify plant identifications or to glean information on the specific locations of plants in Texas.
The PRC collections also benefit the authors of many popular Texas wildflower books, who have consulted the collection in order to ensure the scientific accuracy of the information they present to the public. The PRC houses specimens that are the foundation of such important regional floras as Manual of the Vascular Plants of Texas (D. S. Correll and M. C. Johnston, 1970), Atlas of Vascular Plants of Texas (B. L. Turner et al., 2003), and Flora of the Chihuahuan Desert Region (J. Henrickson and M. C. Johnston, in preparation).
Most significantly, material from the PRC is used for teaching at the university. By studying specimens, students gain an understanding and appreciation of the diversity of plants across the state and the world. Tours are routinely given to classes, as well as to garden clubs and other groups interested in botany. The PRC also publishes an annual journal, Lundellia, which includes scholarly articles on plant systematics written by faculty, students, staff, and associates.