Book Review: Agaricus of North America

Published by Kaylee Walters on

Book Review: Agaricus of North America

Agaricus of North America

Richard W. Kerrigan. Memoirs of the New York Botanical Garden, Volume 114, 2016. xviii + 573 p. NYBG Press, Bronx, NY. ISBN 978-0-89327-536-5. ISSN 0077-8931 $127.99, member price $115.19

In my opinion, publication of Agaricus of North America represents a watershed moment in mycological taxonomic publications. It is extensive, provides a taxonomic philosophy, implements a balance of genomic and traditional kinds of information, is extremely well organized, and includes important historical information. In a few short pages, this review cannot do it justice.

“There is no single guide, technical reference, or monograph to Agaricus in North America, nor to any of our three countries here, nor, with few exceptions, to any region of the continent. This regrettable oversight by modern civilization is clearly an impediment to preparing an adequate inventory of biodiversity here, to say nothing of dining out with a measure of confidence.”

 “This volume is in no sense a monument to anything, but rather a testament to the continuing process of comprehending the unknown. It is a tool, not logos.”

With those words, Kerrigan sets down what is true for all monographs these days: a monograph is a snapshot in time, and always a work in progress. Kerrigan presents an excellent discussion of the difficulty surrounding species concepts, given that evolution is a continuing process and that in some cases specimens representing published names do not exist. His discussion should be required reading for undergraduate and graduate students alike.

This book is a joy to read and use. Although really a tome in the best sense of the term, it is printed on high quality paper, with a spine that is expertly sewn. It is not a field book, but one to be used on return from the field to determine the specimen in hand. Kerrigan includes important commercial and historical information on the cultivation of Agaricus, which has reached an estimated $10 billion in retail value.

This monograph has an extended and very useful presentation on the anatomy of the Agaricus sporophore. Especially detailed is Kerrigan’s discussion of the veil and its relation to the stipe and pileus.  The detail here is excellent and commendable, useful to both professional and amateur mycologists alike. Well-presented is a discussion of the spores of Agaricus and how the length in some species (A. subrufescens, for example) can be bimodal in size distribution and that the spore size differences can be diurnal in production! He gives good information about how to sample for spore size to get a reliable average size.

ITS DNA sequencing is also discussed. Kerrigan makes that point that a level-head must be used in assessing ITS results so as not to overly interpret results nor to under-interpret results. I think his outlook here is wise.

There is a section on “Typification of Published Taxa.” Lecto- or epitypification is provided for nine species, including Agaricus campestris L.  Included are a number of specimens that had been discarded from interim storage in an institution before they were transferred to another institution. It’s handy to have these choices all in one place.

Kerrigan describes 188 taxa in 11 Sections: Bivelares, Chitonoides, Xanthodermatei, Sanguinolenti, Nigrobrunnescentes, Agaricus, Spissicaules, Subrutilescentes, Rarolentes, Minores, and Arvenses. He also recognizes five lineages: ‘tennesseensis’; ‘floridanus’, ‘longuloid’, ‘gyrophragmioid’, and ‘martineziensis’. The top of every page in the taxonomic treatment shows the Section you are in, making it easy to orient where you are in the book.

In the text, a Section includes a spore size scattergram for all the species in the section, and a phylogram, followed by a dichotomous key. Presentation of species descriptions includes, when appropriate, copies of paintings or sketches from the original descriptions, and high-quality photographs.

At the end of the taxonomic treatments are extremely valuable historical, in-depth discussions of the contributions of past mycologists, serving to give short descriptions of many of their species, which are excluded for numerous reasons, and for the earlier mycologists a discussion of their unusual curatorial practices: C.H. Peck, New York State Botanist from 1867 to 1915; W.A. Murrill, originally a mycologist at the New York Botanical Garden; Alexander H. Smith, a student of C.H. Kauffmann and who worked at Michigan State; B.F. Isaacs, MS student of Daniel Stuntz at University of Washington and later a Ph.D. student under A.H. Smith; and A.E. Freeman, doctoral graduate student of Ronald H. Petersen at University of Tennessee.

Near the end this treatment has a well-organized list of critically examined type specimens, followed by an equally well organized list of vouchers examined and sequenced for accepted species. Finally, there is an extended list of accepted species, their synonyms, and associated source of publication.

I wholeheartedly recommend this book. It is an extraordinary publication, perhaps the best organized and well-written taxonomic treatment I have ever gone through; it is a model for anyone attempting to prepare a monograph. Agaricus of North America should be in the library of any professional mycologist who explores these fungi.

Reviewed by:

Steve Carpenter, President Emeritus
Pacific Analytical Laboratory, Inc.
Philomath, OR