Lichens, written by Annie Lorrain Smith in 1921, is a comprehensive guide to the biology, ecology, and classification of lichens. The book begins with an introduction to the structure and morphology of lichens, explaining their unique symbiotic relationship between fungi and algae. Smith then delves into the ecological significance of lichens, discussing their role in soil formation, nutrient cycling, and air pollution monitoring. The bulk of the book is devoted to the classification of lichens, with detailed descriptions and illustrations of the various families, genera, and species. Smith provides a thorough overview of the taxonomic characteristics used to identify lichens, including thallus type, reproductive structures, and chemical composition. In addition to the scientific aspects of lichens, Smith also explores their cultural significance. She discusses the use of lichens in traditional medicine, as well as their importance in art and literature. Overall, Lichens is a valuable resource for anyone interested in the study of lichens, from professional botanists to amateur naturalists. Its clear and concise writing style, coupled with numerous illustrations and photographs, make it an accessible and informative guide to this fascinating group of organisms.This scarce antiquarian book is a facsimile reprint of the old original and may contain some imperfections such as library marks and notations. Because we believe this work is culturally important, we have made it available as part of our commitment for protecting, preserving, and promoting the world's literature in affordable, high quality, modern editions, that are true to their original work.