At the Arizona State University Lichen Herbarium, has a large collection of lichens from Southwestern North America, including many collections from Baja California, Sinaloa and Sonora. This work is a result of the Greater Sonoran Desert Lichen Flora project (now concluded).

The study area is defined broadly to include the Sonoran Desert as defined by Shreve (1951), Mediterranean areas in California and adjacent mountainous regions. In Mexico it includes all of Baja California, Sonora and Sinaloa from Mazatlán north. It also includes the Sierra Madre area of western Chihuahua extending as far south as the Barranca del Cobre (Copper Canyon). In the United States it includes all of Arizona, the desert regions of SE California and coastal Californian areas as far north as San Francisco.
Arizona State University in colaboration with UNAM an other U.S. institutions is about to embark on an investigation of the "Parmeliaceae of Mexico", and consequently will be adding many additional collections from Mexico. The project will support a Mexican post doctoral fellow.

The database of the Lichen herbarium contains of 73 418 registries of samples corresponding to 708 genera and 6659 species.