Microlichens of the Pacific Northwest. 2 volumes. 2017. Many illus. 970 p. gr8vo.

The two volumes comprising Microlichens of the Pacific Northwest provide, for the first time in one place, comprehensive illustrated keys to the genera (Volume 1) and species (Volume 2) of microlichens from the Pacific Northwest of North America. Microlichens (crustose lichens and other lichen forms that often require a compound microscope for study) encompass a vast range of forms and contribute greatly to the biodiversity of the region and the world; their species richness is, however, often unrecognized. These volumes will greatly enhance knowledge and appreciation of these fascinating organisms, as they provide a synthesis of what is currently known about their biodiversity, distribution, and abundance in the Pacific Northwest. Volume 1, Key to the Genera (215 pages), provides a general introduction to microlichens, generously illustrated keys to the genera, a glossary, and an index. It includes 623 illustrations (mostly color photographs and a few black-and-white line drawings) and encompasses 253 genera. Volume 2, Key to the Species (755 pages), provides keys to 1424 species from the Pacific Northwest region that have main entries and 297 additional species with secondary treatments that have been reported from neighboring regions with possible occurrences in the Pacific Northwest, for a total of 1721 species. Brief descriptions of each species are embedded in the keys. Volume 2 includes 479 illustrations (line drawings and b/w photos). While the geographic area covered by the books is the watershed-based boundary of the Pacific Northwestern United States (south of the US-Canadian border, inland to western Montana and northwestern Wyoming, and dipping into northwestern California), the treatments will also be useful in a much broader area of the western U.S. and Canada, as well as the rest of the Northern Hemisphere. The books are intended largely for use by serious amateurs or professional lichenologists. A compound microscope will be necessary to identify many of the species, although some genera and even species can be identified without using a compound microscope.