Floras facilitate the identification of plants from a particular region. This essay reviews the historical development of printed lichen floras utilizing dichotomous keys for North America. In the future ‘virtualfloras' utilizing a more flexible electronic keying system will be possible. Additionally, essential components of such virtual floras include several databases–for characters, collections, images, synonyms and accepted names, literature, and terminology (glossary). Integration of the various components utilizing both centralized and distributed approaches is now possible, and will lead to a comprehensive on-line lichen determination system. Proposed ways, in which the data can be used beyond simple species determination, are also briefly discussed.