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2019 THE GREAT LAKES BOTANIST
Gerould Wilhelm & Laura Rericha. 2017. Flora of the Chicago Region. Indiana Academy of Science, Indianapolis. xviii + 1372 pp., hardcover $125.00. ISBN 978-1-883362-15-7. A planned ebook version is not yet available.
The southern end of Lake Michigan boasts the greatest floristic diversity in the Great Lakes region. Not least among the factors that promote this richness is the presence of numerous specialized habitats in the area. Some of these once covered vast tracts in the Midwest, but are now globally rare and present only as remnants. It is appropriate, then, that this area has long been covered by excellent floras. An early major effort in this regard is Flora of the Chicago Regionby
H. S. Pepoon (Pepoon 1927). Pepoon, a high school teacher, had spent many years studying the flora and preparing the book. For purposes of Pepoon’s flora, the “Chicago Region” was defined as a semicircular area centered just offshore of Chicago, the perimeter of which extended from the moors north of Waukegan, Illinois, past the cities of Zurich, Elgin, and Joliet, Illinois, then into Indiana near Crown Point, running north of Valparaiso, and ending at what is now the Indiana Dunes State Park. The flora was primarily a listing of the plants; there were some keys covering some groups of plants, but by no means all; the entries for the individual species contained brief habitat description and occasionally a brief descriptive phrase. A still valuable feature of Pepoon’s flora is an introductory section of nearly 140 pages describing all the major habitats and floristic regions in the area and illustrated by numerous photographs of the various habitats. This was soon complemented by Donald Culross Peattie’s Flora of the Indiana Dunes (Peattie 1930), which covered two rather ill-defined areas, the “High Dunes Country,” extending along the shore of Lake Michigan from Miller (a section of Gary, Indiana) to the Michigan-Indiana state line, and the “Calumet District,” described as “a great sandy and marshy tract to the west” extending to the Indiana- Illinois state line. In an important advance over Pepoon, Peattie’s flora had full keys and brief descriptions of all taxa covered, which serve as an important complement to the keys in the effort to identify a plant. The individual who arguably dominated the floristic study of the Chicago region for half a century, Floyd Swink, appeared on the scene right after World War
II. Having had an acute interest in plants since his high school days in the 1930s, he then began an association with Dr. Julian Steyermark, a renowned botanist at the Field Museum, who tutored him in botanical matters for the next 13 years (Mohar 2002). Over the ensuing years, Swink learned quickly and intensively explored the flora of the Chicago region. His first book on the flora was A Guide to the Wild Flowering Plants of the Chicago Region(Swink 1953). Not a flora as that term is usually understood, this book is rather an extended key to the flowering species (other than graminoids and ferns) in the Chicago region, defined as a semicircular area centered on Chicago and encompassing an area somewhat larger than that recognized by Pepoon (1927). The key uses a device invented by Page 112 112 THE GREAT LAKES BOTANIST Vol. 58
Swink that is quite different from other keys one may be familiar with, later described by Swink as a “radical departure,” but “highly successful” (quoted in Mohar 2002). The device was an initial list of 26 characteristics, each given a letter from A to Z, divided into 6 categories. The user with an unknown plant would compare the characteristics in the list to create a 6-letter phrase, such as BFJQVX, then go to that phrase in an alphabetical listing of all possible combinations where one or more plants fitting those characteristics would be further distinguished. Before long, Swink took a different tack and published a checklist of all known plants in the Chicago region, now encompassing 22 counties, three in southeastern Wisconsin, 11 in northeastern Illinois, seven in northwestern Indiana, and one in southwestern Michigan (Swink 1969). This area thus was larger than, and encompassed all of, the areas included in all previous floristic publications on the Chicago region. This was the first of what eventually became four editions of Plants of the Chicago Region. This edition rapidly sold out, and a second edition was published just five years later (Swink 1974). Both of these editions lacked keys and descriptions and therefore could not be used to identify plants. Instead, they were meant to be used in conjunction with other books that do have those features. They did, however, include habitat data and associated species for each species included as well as distribution maps (a dot in each county in which the species has been recorded to occur) and, in the second edition, flowering dates. Taxa were arranged, not taxonomically by family, as is the case with most floras, but alphabetically by genus, and then by species within each genus.
Early in 1974, Gerould Wilhelm, having just left the army, joined the staff of the Morton Arboretum in Lisle, Illinois, where Floyd Swink was employed. Two years earlier, Wilhelm, having no experience in botany, had enlisted Swink to assist him in assessing certain potential dredging sites for the army and was impressed with the latter’s extensive knowledge of all the plants they saw (Greenberg 2002). From then on, Wilhelm worked closely with Swink in preparing the third edition of Plants of the Chicago Region (Swink and Wilhelm 1979) and later with the fourth edition (Swink and Wilhelm 1994). Both the third and fourth editions were greatly expanded over previous editions with the addition of identification keys, first to family in the front of the book, then to genus within each family, which appeared alphabetically interleaved with the genera, and finally to species within each genus. But a major addition was a description of the Floristic Quality Assessment, first introduced in these volumes, a methodology devised by Wilhelm to assess the quality of natural areas by assigning all native species in the flora a number from 1 to 10 in order of increasing fidelity to a native habitat and taking the average of all species found in the habitat in question. The higher the average, the greater the quality of the habitat. Ever since, this methodology has been used by botanists and ecologists ever since throughout the Midwest and beyond, as is attested by its use in numerous articles published in the present journal.
With these two editions, botanists, ecologists, and nature enthusiasts at last had an up-to-date means of identifying the plants in the Chicago region and an accurate listing of all the plants in the area, their distribution, and their ecological preferences. But “up-to-date” is a relative term. Beginning around the time of
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the publication of the fourth edition of Plants of the Chicago Region, there was a ferment in taxonomic botany that continues to this day in which wholesale realignments in the relationships of many groups of plants took place, resulting, in many cases, in changes in the scientific names. By 2017, 23 years after the publication of the fourth edition, so many names had changed, and generic assignments altered, that the 1994 edition was becoming increasingly out-of-date. A new generation of young botanists, ecologists, restoration biologists, and nature enthusiasts had grown up in the meantime for whom the old names were mystifying.
Thus, the appearance early in 2017 of Wilhelm and Rericha’s new Flora of the Chicago Region was long awaited and enthusiastically welcomed. As the new title indicates, this is not merely a fifth edition of the Plants of the Chicago Region, although in many ways it is in fact a continuation of the earlier works by Swink and Wilhelm. It continues the alphabetical by genus arrangement; it maintains the dot distribution maps for the same 22-county region; and it continues the practice of the earlier volumes of listing numerous plant associates of each species included. But there is much that is new, and what is new justifies the treatment of this volume as a new work in itself. Most importantly, descriptions are provided for every taxon in the flora, the first time a flora covering any part of the Chicago region has contained descriptions since Peattie (1930). Although they are brief, they are concise and cover the essential identifying characteristics, thereby serving as an important confirmation or check on the process of keying out an unknown plant. In addition, excellent and accurate line drawings illustrating important identifying characteristics accompany many of the entries. For the first time in any flora covering this region, and perhaps for the first time in any flora anywhere, many of the entries contain lists of insect, bird, and other animal associates of the plants, whether as pollinators, herbivores, or otherwise. Moreover, these are not always bare-bones listings—often a description of the activities of the animal associates is given. An important feature carried over from the earlier volumes by Swink and Wilhelm that should not be minimized is the inclusion under each taxon of alternative names used for that taxon by any of several older floristic works covering all or part of the same area, including large regional floras that cover the entire northeastern United States and Canada. This can be very useful in comparing the treatment of a taxon here with that offered by other authors.
So, too, much additional information has been added at the front and back of the book. After a detailed Introduction explaining the contents of the book and how to use it, there is a classification of the natural divisions of the floral area, based on geological and vegetational distinctions, accompanied by a full-color map, and a detailed description of each of the many plant communities in the area with 42 color photographs. At the end of the book, there is an index to plant names, including both scientific and vernacular names, and index to the animal names that have been mentioned in the individual species entries, followed by a similar index to rusts, smuts, mildews, and other fungi. A list of all individuals given as authorities for the names in the Florais provided, explaining all abbreviations and giving the birth and death dates of each. Finally, the book concludes with a detailed glossary, 24 color plates, and an extensive bibliography of litera
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ture cited throughout the book. As if that were not enough, the editor who saw this magnificent work through the press, Bill McKnight, asked the senior author to provide an “End Note, a Retrospective and Perspective,” which details Wilhelm’s 45 years of botanical study in the Chicago region, itself a valuable addition to the history of floristic endeavor in this rich botanical area.
I cannot end, however, without discussing what I view as a significant drawback, and that is the sometimes rather idiosyncratic choices in classification made by the authors. The ferment referred to earlier in taxonomic botany continues, and the end is not in sight. Nevertheless, a number of significant conclusions have been reached that are widely accepted among botanists, and most modern floras incorporate these findings. There is certainly room for some disagreement among authors, even while adhering substantially to the general consensus on classification. The book under review is no different; in large measure, it incorporates modern findings and thereby satisfies the longing for an up-todate flora of the region. But there are some significant departures that are not explained. For example, the Liliaceae, once treated as a large unwieldy family that was long recognized as unnatural, has in recent decades been pared down to a group of about 15 or 16 genera and about 600 species that has been widely accepted as natural by botanists for more than two decades (see Givnish et al. 2016 and references therein). But Wilhelm and Rericha make it much smaller still, recognizing among local genera only Erythronium, Lilium, and the non-native Tulipa as belonging to the family. Other genera, all but universally recognized as belonging to the core Liliaceae, are relegated elsewhere: Medeola to the Trilliaceae, where it clearly does not belong, despite a superficial resemblance to some species of Trillium; and Clintonia and Streptopus to the Convallariaceae, where they keep company with genera that are now conceded to be only distantly related to the Liliaceae and that belong in fact to a separate order, the Asparagales. Similarly, the Scrophulariaceae, formerly a large family widely understood to be unnatural, has also in recent decades been dramatically dismembered, keeping in the core Scrophulariaceae only two local genera, the native Scrophularia and the non-native Verbascum. The remaining local genera have been moved to several other families, including Orobanchaceae, Phrymaceae, Plantaginaceae, and Linderniaceae. Although this re-arrangement is widely accepted among botanists, Wilhelm and Rericha “acquiesce” in it only to the extent of accepting the transfer of certain genera to the Orobanchaceae, retaining all the rest in their Scrophulariaceae. Despite a lengthy explanation of their choices, it all seems to come down to a matter of taste (or perhaps distaste) rather than a reasoned rejection of the current consensus. The last few decades have also seen the combination of pairs of families that were previously considered distinct, but widely understood to be closely related, such as Apocynaceae/Asclepiadaceae, Boraginaceae/Hydrophyllaceae, Campanulaceae/Lobeliaceae, Papaveraceae/Fumariaceae, and Amaranthaceae/Chenopodiaceae (in each case, the first name of a pair is the name currently used for the combined family). Despite the widespread acceptance of these combinations, Wilhelm and Rericha keep these pairs separate without providing a reason.
At the generic level, perhaps the most egregious departure from current understanding is the recognition of Jussiaea as distinct from Ludwigia. The authors
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state that to “lump this genus with Ludwigia certainly is au courant, but to do so obfuscates the definitive morphological distinctions: stamens twice the number of petals and elongate fruits more than twice as long as wide” (italics in the original). But the current joining of these two genera is not merely “au courant.” It is based on solid biological grounds. The traditional Jussiaea and Ludwigia were separated solely on whether there were one whorl of stamens (Ludwigia) or two (Jussiaea). The distinction in dimensions of the fruit may hold for the local species, but does not do so on a world-wide basis. More than forty years ago, I asked Peter Raven, the world’s authority on the family to which these genera belong (Onagraceae), why these genera were joined. He explained that species of Jussiaea were each actually more closely related to other species of Ludwigia than they were to each other. In other words, to recognize both genera would render both unnatural, or in modern parlance, they would not be monophyletic groups, the most basic criterion in botanical classification for at least the last half century. The inclusion of Jussiaea within Ludwigia has been the consensus at least since 1955 (Wagner et al. 2007). Similar departures in other genera can be mentioned in passing: Anemonella thalictroides (currently Thalictrum thalictroides); Erophila verna (currently Draba verna) (see Al-Shehbaz et al. 2010, who explain that Erophila differs from Draba in only a single character, which is furthermore unreliable, and that removing Erophila from Draba would render the latter non-monophyletic).
Both the book under review and the earlier volumes by Swink and Wilhelm are characterized by the virtually complete absence of any reasons given for their taxonomic choices. Rather, differences of opinion are introduced with sentences such as “Some authors consider this species conspecific with Erophila verna,” or “Some authors call this plant Thalictrum thalictroides,” or “Some authors include this genus with the Montiaceae.” One could easily conclude that, by and large, the taxonomic choices are made on the basis of taste rather than taxonomic reasoning.
None of this gainsays the fact that Swink, Wilhelm, and Rericha are superbly outstanding floristicians and field botanists, who are concerned with the questions of what grows in the flora area, where does it grow, and how do you identify it; what are its ecological and community circumstances. Despite my quibbles about classification, this book remains one of the finest floristic works anywhere. It represents an enormous amount of painstaking field, herbarium, and literature work, and presents with great completeness and accuracy the current knowledge of the flora of the Chicago region, a knowledge that has been, in substantial part, developed by the authors themselves. Again, despite my quibbles, the names and classification used in this book are overwhelmingly in accord with current consensus, and for that reason, although I cannot recommend it as the last word in nomenclature or classification of our local plants (those who need that sort of information can easily find it elsewhere), it is highly recommended to all who have a need for knowing what grows in this area, where it grows, and how to identify it. I live in the area covered by this Flora, and I refer to it on an almost daily basis. I have gained a wealth of insight about our local flora from this magisterial work, and I would not be without it.
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Al-Shehbaz, I. A., M. D. Windham, and R. Elven. (2010). Draba, Pp. 269–347 in Flora of North America, Volume 7: Magnoliophyta: Salicaceae to Brassicaceae. Flora of North America Editorial Committee, editors. Oxford University Press, New York, N.Y.
Givnish, T. J., A. Zuluaga, I. Marques, V. K. Y. Lam, M. S. Gomez, W. J. D. Iles, M. Ames, et al. (2016). Phylogenomics and historical biogeography of the monocot order Liliales: Out of Australia and through Antactica. Cladistics 32: 581–605.
Greenberg, J. (2002). A natural history of the Chicago region. The University of Chicago Press, Chicago, Illinois.
Mohar, P. (editor). (2000). A congenial fellowship: A botanical correspondence between Charles C. Deam and Floyd A. Swink 1946–1951. Shirley Heinze Environmental Fund, Michigan City, Indiana.
Peattie, D. C. (1930). Flora of the Indiana Dunes. Field Museum of Natural History, Chicago, Illinois.
Pepoon, H. S. (1927). Flora of the Chicago region. The Chicago Academy of Sciences, Chicago, Illinois.
Swink, F. (1953). A guide to the wild flowering plants of the Chicago region. Rockrose Press, Chicago, Illinois.
Swink, F. (1969). Plants of the Chicago region: A checklist of the vascular flora of the Chicago region with notes on local distribution and ecology. The Morton Arboretum, Lisle, Illinois.
Swink, F. (1974). Plants of the Chicago region: A checklist of the vascular flora of the Chicago region with notes on local distribution and ecology, second edition. The Morton Arboretum, Lisle, Illinois.
Swink, F., and G. Wilhelm. (1979). Plants of the Chicago region, third edition. The Morton Arboretum, Lisle, Illinois.
Swink, F., and G. Wilhelm. (1994). Plants of the Chicago region, fourth edition. Indiana Academy of Science, Indianapolis.
Wagner, W. L., P. C. Hoch, and P. H. Raven. (2007). Revised classification of the Onagraceae. Monographs in Systematic Botany 83: 1–240.