The Lichen Genus Cladonia in North America - Paperbackby John W. Thomson (Author) The lichen genus Cladonia includes some of the very common ground cover plants in the United States and Canada. Before the compiling of this volume, the published results of research carried out with respect to this lichen genus were widely scattered, in many different languages, and often very difficult to locate or translate. This manual is an extensive compilation of the available information necessary for the