by Jessica L. Allen and James C. Lendemer
Yale University Press, 2021
Our sprawling East Coast cities, often visited for their history and culture, don’t usually attract naturalists in search of wild flora. But perhaps that will change: Urban Lichens: A Field Guide for Northeastern North America, introduces a millimeter-high jungle that encrusts urban architecture across northeastern North America.
Written by Jessica L. Allen, assistant professor of integrative plant biology at Eastern Washington University, and James C. Lendemer, associate curator at New York Botanical Garden, Urban Lichens is a compact guide to more than 60 lichens commonly found in cities as far west as Chicago. Illustrated with beautiful macrophotography, the purpose of this specialized guide is to introduce city dwellers and visitors to the wild lichens hiding in anthropogenic habitats. The book is broken into three sections: an introduction with background information on lichens generally and urban lichen-hunting specifically; species profiles; and a collection of supporting resources.
The introductory section includes the usual background I would expect from a guidebook: an overview of lichen biology, how to identify them, and where to find them. I was pleasantly surprised to see summaries of other notable lichen topics, including lichen roles in human culture, wild ecosystems, and urban environments. The authors also discuss lichens and air pollution. Many common lichens are sensitive to air quality and after the Industrial Revolution were nearly driven out of urban areas.
As with other lichen guidebooks designed for the citizen naturalist, Urban Lichens divides its species profiles into crustose, foliose, and fruticose categories, terms that refer to the growth shapes of lichens. Each section is then subdivided by color. While this categorization isn’t based on taxonomy, it does make the book user-friendly for non-scientists. It’s easy to flip through and quickly find lichen photos that are a visual match for a wild specimen. The end of the species profile section includes a dichotomous key for formal lichen identification.
The resources section presents a complete list of New York City lichens, an illustrated glossary, and bibliography with further reading. The glossary is especially useful for those new to lichens, as they have many uniquely named features. The list of New York City lichens may serve as a life list for the aspiring urban lichenologist.
With its small stature and durable, water-resistant cover, this is an easy book to add to any naturalist’s perambulations. Even for those who rarely visit major urban centers, the introductory section reads like a CliffsNotes version of the imposing Lichens of North America and is small enough to use as a pocket glossary. Many of the species’ profiles cover lichens familiar to me from my own more rural home.
That this guidebook can exist is a message of hope: cities’ tiny lichen jungles were nearly felled by air pollution, but in recent decades, as urban air quality has improved, lichens have been regrowing and flourishing in northeastern cities once again. Let’s celebrate their comeback by taking the authors’ invitation to start our own explorations of this miniature ecosystem living on our buildings, monuments, and sidewalks.