The Secret World of Lichens: A Young Naturalist’s Guide

Lichens may be one of the most overlooked life forms by those looking for showy plants or captivating animals because they are neither plant nor animal. The Secret World of Lichens: A Young Naturalist’s Guide reveals the ‘secret world’ of these unique organisms that are the product of a close relationship between a fungus and a “photosynthesizing” or energy producing partner, such as algae. They come in a wide variety of colors and shapes, grow “in virtually every terrestrial environment” on earth (and some in space), and play valuable roles in nature and for humans. The “Introduction” offers a definition, a description of the three main forms, an explanation of lichen structure and reproductive modes, details of growth and longevity, and some uses.

A second section presents a random selection of 38 of about 20,000 species found worldwide. The guide, complete with full colour closeup photos, details where to find each specimen, brief descriptions of size, shape and colour, uses and, for a few, other special features. A “Glossary” helps with definitions of bolded terms within the text. There is no table of contents or index. A few resources for further investigation would have been a good addition.

The book gives an introductory understanding of lichens, with language and writing style most accessible to capable young readers. Because lichens are “complex life forms”, explanations have a fairly high level of complexity: the section on reproduction and structure assumes the reader has a basic understanding of vegetative and sexual modes of reproduction. To assist with this, a detailed diagram is included, with labels that are defined in the “Glossary”. A patient reader will connect all the parts. In the discussion of growth, sizes are given in millimeters, but a comparison to something familiar would help visual learners.

Explanations of uses of lichens will intrigue readers, given that the organisms may produce over 1000 chemicals that create colours (useful for dyes). A little more information might enhance understanding of the term ‘antibacterial properties’: e.g. what familiar products might contain usnic acid? Their toxic properties are described as being “used to poison foxes and wolves in Scandinavia”; readers may wonder why. Lichens as indicators of air pollution is well-explained with concrete examples. Likewise, animal uses (nesting material, camouflage, food) are clearly stated.

The author has chosen 38 “interesting and beautiful” species to illustrate with excellent closeup photos. Most of the text portions here detail where the species is found, the shape and colour, size, and use. A few depart slightly from this repetitive pattern by adding a special feature, e.g. one rolls freely like tumbleweed, the common name for another is Dead Man’s Fingers, one is thought to have been used as Christmas tree tinsel. These extra tidbits of information make those particular lichens more memorable. But names like Devil’s Matchstick, Fairy Puke, and Toy Soldiers lichens are fun. Just as some readers might find size comparisons relating to growth useful, a visual measure would help to picture the actual size in the closeup photos: e.g. a coin strategically placed in the image would certainly give a clear idea of how tiny the Yellow Collar Stubble Lichen really is, when, at less than 1 millimeter tall, it fills the whole picture frame.

Overall, this well-researched guide will be a useful introduction for those curious about this fascinating life form, encouraging us to pay more attention to them. Thanks to its information, I’ve found what appears to be a Fruiting Honeycomb Lichen (Hypogymnia lophyrea) on the hawthorn tree in my yard!