Created in response to requests from longtime users, this addition to the acclaimed book, Lichens of North America, compiles updated and expanded keys for the identification of these fascinating organisms. An ideal laboratory resource, this large spiral-bound volume covers over 2,000 species of lichens indigenous to the continent. There is no comparable volume available for classroom, workshop, or private use. The revised keys are an indispensable identification tool for botanists, students, scientists, and enthusiasts alike.