A. Michael Powell, Distinguished Professor Emeritus of Biology and Director of the Sul Ross State University Herbarium (SRSC), holds a Ph.D. in Botany from The University of Texas at Austin (1963). His research interests include plant systematics, emphasizing monographic studies of composite genera in the southwestern United States and Mexico; chromosome numbers of North and South American plants, mostly composites; floristics of the northern Chihuahuan Desert region (including gypsum habitats); experimental hybridization studies in composites and cacti; rare plants of Trans-Pecos Texas; and native plant horticulture. He is author or co-author of more than 120 articles in professional publications and several books concerning the flora of western Texas, including Trees and Shrubs of Trans-Pecos Texas and Adjacent Areas, Grasses of the Trans-Pecos, and Cacti of the Trans-Pecos and Adjacent Areas.

Richard D. Worthington, Associate Professor Emeritus of Biology at The University of Texas at El Paso and Curator of the UTEP Herbarium, holds a Ph.D. in Zoology and Ecology from the University of Maryland, College Park (1968). Since the mid-1970s, his research has focused on plant diversity on mountains of varying sizes in the southwestern United States and the documentation of the flora across southern New Mexico and western Texas. His extensive plant collecting activities—mostly in the southwestern U.S., Mexico, and the Caribbean—have yielded 39,000 collection numbers. He is author or co-author of numerous articles in professional journals. Knowledge about the Trans-Pecos flora and biota has been significantly augmented through numerous issues of his “Floristic Inventories of the Southwest” program.

Shirley A. Powell is a retired high school science teacher with an M.S. in Biology from Sul Ross State University (1973). She taught biology, chemistry, and physics for 30 years and has extensive field experience collecting and photographing gypsophiles, cacti, and other plants native to the Texas mountains and desert. She is co-author of numerous journal articles as well as two books, Native Plants in Landscaping (2005) and Cacti of Texas—A Field Guide (2008). Powell is also a botanical illustrator and curatorial assistant at SRSC. She has served as a consultant for the Texas Education Agency and currently serves as president of the board of directors of the Chihuahuan Desert Research Institute.