The first botanical specimens at The University of Texas were deposited in the 1890's, although it was not until the end of that decade that the first botanist joined the University. The first curator was Dr. Mary S. Young, an enthusiastic and adventurous collector, who took charge of the herbarium in 1912. During the summers, Young traveled to west Texas collecting in the Guadalupe, Chinati, Davis and Chisos mountains, amassing the largest collections of west Texas plants since those of Charles Wright during the United States - Mexican Boundary Survey in the 1850's. She also collected less intensively in many other parts of the state. Dr. Young increased the herbarium holdings from 2,500 specimens to 16,000 at the time of her death in 1919.
For the next 45 years (until 1958), the herbarium was directed by Dr. Benjamin Carroll Tharp, who shaped the herbarium's growth from 16,000 to 200,000 specimens and collected extensively in Texas. In 1945, Dr. Fred A. Barkley became the new curator of the herbarium, the first curator in many years. Although he was curator only until 1948, he had a major effect. He pursued an active collecting program in both Texas and Mexico and initiated exchange programs with other institutions, thereby greatly increasing the herbarium's Latin American holdings. After he left, there was no curator again until 1975.
In 1958 Dr. Billie L. Turner took the helm of the TEX herbarium, subsequently the Plant Resources Center. In 1961 Marshall C. Johnston joined the Botany faculty. Through the combined efforts of Turner and Johnston and their students, the holdings of the herbarium increased by 100,000 sheets between 1964 and 1970, bringing the total to 300,000 by 1970. In the mid 1970's the Plant Resources Center, an independent research institute in the College of Natural Sciences, was formed to encompass The University of Texas Herbarium, the Lundell Herbarium, a program on the rare and endangered species of Texas, and associated laboratory facilities. In 1978 Dr. Beryl S. Simpson joined the Botany faculty; she assumed the directorship of the Plant Resources Center upon Dr. Turner's retirement in 2000, and Dr. José Panero, an Asteraceae specialist on the faculty since 1996, became the Associate Director.
The Billie L. Turner Plant Resources Center (TEX-LL) with over 1,000,000 specimens is the largest herbarium in the southwestern United States and ranks fifth among U.S. university herbaria and twelfth across the nation. TEX-LL, with about a quarter of its specimens from Texas, has the largest holdings of Texas plants in the world. Nearly one half of the specimens at TEX-LL are from Latin America, with an especially strong representation of Mexico and northern Central America. Presently the number of vascular plant collections inserted in the herbarium is growing at an approximate rate of 16,400 specimens per year.
The vascular plant collection at UT contains many unique collections that are represented only in TEX-LL, or in very few other herbaria. Complete or nearly complete sets include the collections of C. L. and Amelia Lundell, M. C. Johnston, J. Henrickson, R. Runyon, E. Contreras, D. Gentle, E. Matuda, and B. L. Turner. The PRC also has significant holdings of D. S. Correll, S. F. Blake, G. B. Hinton et al., H. N. Moldenke, C. H. Muller, W. A. Silvius, and I. M. Johnston as well as incomplete sets of C. G. Pringle and R. McVaugh. The Plant Resources Center is rich in types with over 8000 taxa represented in its type collection.
The PRC excels in holdings Asteraceae from around the world, with over 200,000 sheets. This large concentration of composites is partly due to the acquisition of the S. F. Blake collection of Asteraceae by the Lundell Herbarium. This large private collection was assembled by the foremost Asteraceae worker of the 20th century. Because of his willingness to identify Asteraceae from throughout the world, Blake amassed not only a large collection, but a very diverse one, both systematically and geographically.
The Blake collection of Asteraceae is intercalated with the very large TEX collection of mostly American and Mexican Asteraceae assembled by the 60 or more monographers (most as students and faculty at UT, especially B. L. Turner and his students) who worked in the Southwest U.S. and Mexico for over 40 years. Comparatively few of these collections have been widely distributed among other U.S. institutions.
Because of the research interests of the staff and graduate students, comprehensive New World collections have been accumulated for the Chloranthaceae, Euphorbiaceae, Fabaceae, Fagaceae, Krameriaceae, Lamiaceae, Polygalaceae and Rhamnaceae. Also strongly represented are the Boraginaceae, Poaceae, and Scrophulariaceae. With the acquisition of the Lundell Herbarium, TEX-LL became a major resource for material of the Celastraceae, Eriocaulaceae, Myrsinaceae, Sapotaceae and Verbenaceae.