This book covers all the known firmosses and clubmosses that occur within the six states of New England (though the book is applicable to the entire northeastern quadrant of North America). This detailed treatise includes introductory chapters on taxonomy and morphology, identification keys, color images, range maps, comprehensive descriptions of the plants, and taxonomic/nomenclatural notes that assist with understanding the species in New England. Two new genera (Dendrolycopodium and Spinulum) are named in this reference, as well as two new firmoss hybrids. All hybrids are provided descriptions to assist with identification of individual plants. Anyone interested in firmosses and clubmosses, especially for conservation purposes, will appreciate the detail involved. Included within this 105-page reference is a key to the genera of firmosses and clubmosses of the world.