William A. Weber is Professor and Curator Emeritus of the Herbarium, University of Colorado Museum of Natural History and Fellow of the Linnean Society of London. A highly acclaimed author with over 65 years of botanical experience in Colorado, he has written extensively on the flora of Colorado, including Rocky Mountain Flora (UPC 1991), A Rocky Mountain Lichen Primer (with James N. Corbridge, UPC 1998), and three books with Ronald Wittman: Bryophytes of Colorado (Pilgrims Process 2010), Colorado Flora: Western Slope (UPC 2001) and Colorado Flora: Eastern Slope (UPC 2001).