The Literature of Systematic Botany

CHAPTER XII THE LITERATURE OF SYSTEMATIC BOTANY Publications dealing directly or indirectly with the systematic, aspect of botanical science have always held a conspicuous place in botanical literature; indeed, a mere list of titles would consume hundreds of pages. To keep the size of this chapter down to proper proportions relative to the rest of the book, the student will be given here but a few representative examples of different phases of the subject, especially since much of the literature is hardly within the grasp of the beginner but belongs in an advanced course. The following table of contents of this chapter will aid in finding any book that is cited here: Media for Taxonomic Publication Page 305 The Pearly Classics 306 Fundamental Principles Morphological 307 Fundamental Principles Genetic, Etc 309 Rules of Botanical Nomenclature 312 World Floras and Taxonomic Systems 314 Regional Floras and Manuals 316 Taxonomic Treatment of Limited Groups 319 Cultivated and Economic Plants 322 Nontechnical Floras 324 Paleobotany 326 Indexes, Catalogues, Etc 327 Miscellaneous 329 MEDIA FOR TAXONOMIC PUBLICATION The earliest botanical works were written before the invention of the printing press and took the form of manuscripts, often bound in book form. Some of the most important of these have since been copied either as facsimile impressions or by printing, with or without translation. In recent years taxonomic publication has taken varied forms research articles, monographs, general treatises, manuals, etc. As for American journals, the Bulletin of the Torrey Botanical Club was formerly given over quite largely to taxonomic work, but in 305 306 A TEXTBOOK OF SYSTEMATIC BOTANY recent years it has become more general. Those that are now devoted especially to this field are American Midland Naturalist, Rhodora, Annals of the Missouri Botanical Garden, Journal of the Arnold Arboretum, Brittonia, Phytologia, Madrono, Darwiniana, Lloa. Lloydia, American Fern Journal, and Castanea. From the standpoint of establishing priority in the publication of names and descriptions of groups, all botanical works jour- nals, books, bulletins, etc. in regular circulation are given equal recognition, and, indeed, priority can be established through works not strictly botanical, although their use is unfortunate, since articles they contain may easily be overlooked by those most interested in them. To discourage the publication of descriptions of species and other groups in obscure places, and especially in languages that are little used, recent rules have prescribed that a Latin diagnosis must be given in order to establish priority of publication. THE EARLY CLASSICS In the older literature a few works stand out as remarkable productions for the period in which they were written. Most of these have profoundly influenced the development of the science. Enquiry into Plants. Written by Theophrastus in nine books. Translated into English by Sir Arthur Hort in 1916; Loeb Classical Library, Harvard University Press. Published in two volumes with the Greek text and the English translation on opposite pages, giving a total of 908 pages. This is the most important of the botanical writings of Theo- phrastus and the oldest botanical work of value existing today. It contains much real botanical information mixed with specu- lative philosophy and expresses freely the beliefs of the times, although in many cases the author casts doubt upon the super- stitious ideas that he records. De Re Rustica. Written by Marcus Porcius Cato more than a century before Christ and printed in 1494; Loeb Classical Library, Harvard University Press, 1934. The book is devoted largely to agricultural and horticultural practices, methods of propagation, culture, varieties, etc., but plants are quite generally designated binomially, and many of these names are still in use. Said to be the oldest botanical work written in Latin. THE LITERATURE OF SYSTEMATIC BOTANY 307 Prodromus Systematis Naturalis Regni-Vegetabilis. By A. P. de Candolle, University of Geneva, and others. Seventeen volumes and four index volumes, 1824-1873; published by G. Masson, Paris. This extensive work, by far the greatest treatise of its day on systematic botany, attempted to describe all known plants and arrange them according to the natural system of de Candolle. 1 After the death of this great botanist in 1841, the work was continued for more than 30 years by his associates. Genera Plantarum. By Carolus Linnaeus, Upsala University. Fifth edition, 1754, 500 pages, unillustrated. This edition is official in establishing the limit of priority for generic names. It describes 1,105 genera of plants of all kinds, citing the authority for the name in most cases. In general, the generic descriptions of the seed-bearing plants are restricted to the flower, fruit, and seed, ignoring vegetative portions. Species Plantarum. By Carolus Linnaeus, Upsala University. First edition, 1753, two volumes, 1,200 pages, unillustrated; facsimile edition, W. Junk, Berlin. In this, the most used of the early botanical classics, Linnaeus assembled under their genera practically all the species described up to that time, using very largely the binomial system but indicating varieties in some cases. Generic descriptions were not included. The work was partly the A result of his own observations and partly compilation. few previously published descriptions were overlooked, but the u Species Plantarum" was such a landmark in nomenclatural development that it was adopted as a starting point for priority in botanical names. FUNDAMENTAL PRINCIPLES MORPHOLOGICAL The orderly taxonomic work of today is based on many principles that are the results of much painstaking research. Some of these have been known so long that their origin is obscure; others represent bold advances taken in recent times. The older works deal mostly with gross morphology and organization into categories, the newer ones with the findings of cytology, genetics, ecology, and plant geography. The Phylogenetic Taxonomy of Flowering Plants. By Charles E. Bessey, University of Nebraska, Ann. Mo. Bot. Gard., 2, 1915, 1 "Th<5orie Elemental de la Botanique," 1st ed., 1813; 2d ed., 1918. 308 A TEXTBOOK OF SYSTEMATIC BOTANY 155 pages, illustrated by one figure showing graphically the author's ideas of the relationships of the angiosperms. He sets forth many principles of taxonomy and from these constructs a phylogenetic system of classification of the angiosperms. His principles and system have steadily gained favor, although they have been found open to improvement. This represents the only attempt of an American botanist to construct a system of classification, and it is very meritorious. Descriptive Systematic Botany. By A. S. Hitchcock, U.S. Department of Agriculture. First edition, 1925, 216 pages, unillustrated; John Wiley & Sons, Inc. An excellent reference book on many topics relating to collecting, identifying, and the scientific arrangement of plants. The different codes of nomenclature that had been proposed up to that date are presented in comparison. The Generic Concept in the Classification of Flowering Plants. By B. L. Robinson, Harvard University, Science, 23: 81-92, 1906. The author here sets forth ideas regarding the correct delineation of genera and seeks to discourage the making of new genera on insufficient grounds. Aspects of the Species Question. By C. E. Bessey, N. L. Britton, J. C. Arthur, D. T. MacDougal, F. E. Clements, and H. C. Cowles, Amer. Nat., 42: 218-281, 1908. A symposium giving a masterful presentation of the best American ideas on the species concept and especially on the problem of finely divided species or subspecies. Later concepts have since been proposed. The Concept of the Genus. A symposium by Harley Harris Bartlett, Edgar Anderson, J. M. Greenman, Earl Edward Sherff , and W. H. Camp, Bui Torrey Bot. Club, 67 : 349-389, 1940. The subject is presented by experienced taxonomists from several viewpoints, but that of the experimental approach of geneticists and ecologists receives only passing mention. Mass Collection. By Edgar Anderson, Ralph 0. Erickson, and Norman O. Fassett, Ann. Mo. Bot. Gard., 28: 287-374, 1941. This series of papers explains that for research purposes samples of significant parts taken from a considerable number of individ- uals of a plant population in a given locality, representing a species, subspecies, variety, or race, have great advantages over single specimens taken in the usual way. Methods are given for sampling, preserving, and using such mass collections. THE LITERATURE OF SYSTEMATIC BOTANY 309 Origin of Species. By Charles Darwin. First edition, 1859; sixth edition, 1893. Two volumes, 305 and 339 pages, respec- tively; bound together unillustrated ; D. Appleton-Century Com- pany, Inc., New York. This book, preceded by the brief expositions of Wallace and Darwin on the same subject a year earlier, constitutes the first adequate presentation of the theory of the evolutionary origin of living things. It is written in the style of a research publication, referring to previous statements by others, submitting evidences, and drawing conclusions. It is the forerunner of a long series of works on evolution by Darwin and numerous other writers. Evolution by Means of Hybridization. By J. P. Lotsy. First edition, 1916, 166 pages and 2 illustrations; Martinus Mjhoff, The Hague. A discussion well adapted to student use. The author dwells especially on the part played by conjugation in the formation of new species and varieties and thus paves the way for the modern genetic and ecological conceptions, i.e., the " experi- mental method" of taxonomy. What Evolution Is. By George H. Parker, Harvard Univer- sity. First edition, 1926, 173 pages and 4 pages of illustrations; Harvard University Press. A highly authoritative, dispassionate presentation of the history, evidences, and mechanism of evolu- tion as it has been disclosed by more than half a century of inves- tigation by many careful workers. The book is suited to students and general readers. Evolution for John Doe. By Ward Henshaw. First edition, 1925, 354 pages, illustrated; The Bobbs-Merrill Company. The author, a layman, has studied the subject from all angles and here presents a good, readable account of it that will appeal to other laymen. Origin through Evolution. By Nathan Fasten, Oregon State College. First edition, 1929, 456 pages, and 75 illustrations; Alfred A. Knopf, New York. This book gives, in readable form, a well-rounded account of the development of our ideas concerning organic evolution, with emphasis on the evidences bearing on the subject and the laws governing its operation. FUNDAMENTAL PRINCIPLES GENETIC, ETC* Por centuries plants were classified on the basis of their morphology and anatomy, and certain principles were evolved to 310 A TEXTBOOK OF SYSTEMATIC BOTANY guide taxonomists in the interpretation of their observations. Some references to these principles are cited above. More recently other branches of botany genetics, ecology, etc. have added new lines of evidence based on both observation and experiment. Some of these are reviewed below. Principles of Genetics. By Edmund W. Sinnott and L. C. Dunn, Columbia University. Third edition, 1939, 408 pages and 147 illustrations; McGraw-Hill Book Company, Inc. This book serves admirably to give the genetic evidence concerning the methods by which evolution takes place in plants and animals. The New Systematics. Edited by Julian Huxley, England. First edition, 1940, 583 pages, illustrated; The Clarendon Press, Oxford, England. Twenty-two chapters, each written by a different author, who had specialized in the field covered and represented different nationalities. The book covers in a thorough and authoritative way the newer researches in ecology, plant geography, paleontology, genetics, and other fields that have a bearing on taxonomy and where possible correlates them with the older morphological findings and conclusions. It is the fullest exposition up to 1940 on the experimental method in taxonomy. Genetics and the Origin of Species. By Theodosius Dobzhan- sky, Columbia University. Second edition, 1941, 446 pages, illustrated; Columbia University Press. Although written by a zoologist, this book contains much illustrative material from the plant kingdom. The fundamental principles brought out in explanation of the mechanism of evolution are applicable to both animals and plants and represent the author's interpretation of the genetic researches in this field. The Genotypical Response of the Plant Species to the Habitat. By Gote Turesson, Institute of Genetics, Askarp, Sweden, Hereditas, 3: 211-350, 1922, illustrated. The work was based largely on transplants made from one environment of central and northern Europe to another. Studies were made on the anat- omy, cytology, and gross morphology of the transplants and on the results of hybridization. Here are introduced the terms cenospecies, ecospecies, ecotypes, and ecophenes as categorical equivalents of genera, species, subspecies, and variants but in a different way, the latter being based on morphology and the former on genetic and ecological experiments. THE LITERATURE OF SYSTEMATIC BOTANY 311 The Concept of Species Based on Experiment. By Jens Clausen, David D. Keck, and Wm. M. Hiesey, Amer. Jour. Bot., 26: 103-106, 1939. A concise presentation of the newer concept of species and other lower categories. In contrast with the older conceptions based on gross morphology, this newer conception is based on experimental work in which closely related plants are crossed and the resulting offspring (if any are produced) are studied under different environmental conditions, some plants being isolated and others given a chance to interbreed. Stability in the product under experimental conditions determines its category species, subspecies, etc. Experimental Studies on the Nature of Species. By Jens Clausen, David D. Keck, and William M. Hiesey, Carnegie Institution of Washington at Stanford University, Publication No. 520, 1940. Part I, on "The Effect of Varied Environments on Western North American Plants," has 452 pages, illustrated. Continuing the work begun by the late Dr. Harvey Monroe Hall of the same institution, the authors have transplanted a considerable number of species of perennials into three dissimilar regions to test the effects on them of the wide range of ecological conditions altitude, moisture, temperature, etc. found in California. Some mention is made of chromosome numbers and other cytological data, but the work deals mostly with ecology in relation to taxonomy, the cytological and genetic aspects being treated in a companion volume now in preparation. The Role of Isolating Mechanisms in the Differentiation of Plant Species. By G. Ledyard Stebbins, Jr. Biological Symposia, 6: 217-233, 1942. This is representative of the recent papers reporting the results of researches undertaken to show the necessity of isolation for the prevention of cross-fertilization, if species and other lower categories are to become established following hybridization. It also discusses the different kinds of isolating mechanisms and their origin. It has a valuable bibliography on the subject. Chromosome Number and the Relationship of Species in the Genus Viola. By Jens Clausen, Ann. Bot. [London], 41 : 677-714, 1927. Based on original investigations and on citations from other cytologists, the chromosome numbers of more than forty species of Viola are given. Fourteen different numbers, ranging from six to thirty-six, are given. In a phylogenetic study the 312 A TEXTBOOK OF SYSTEMATIC BOTANY number, size, and shape of the chromosomes are compared with the morphological characters. Through crossing it was found that individuals sufficiently identical in morphology to be classed as the same species can be derived from unlike parentage. Some explanations are offered for partial and complete sterility in the offspring. RULES OF BOTANICAL NOMENCLATURE After Linnaeus had convinced the biological world that the binomial system of nomenclature was the best one to use, the naming of plants was extensively carried on by many botanists who were widely separated and working independently, and much confusion resulted. To secure greater uniformity in procedure the leading botanists of the world have held a number of international congresses and adopted rules of procedure. The rules that they adopted and that survived the action of later congresses are given below. Botanical nomenclature has become so complicated that a summary of the most important rules is given on pages 234 to 236 of this book. Codes of Nomenclature and Botanical Congresses. By Herbert C. Hanson, Amer. BoL, 31 : 114-120, 1925. A brief review of the national and international botanical congresses up to 1910, with references to the publications of their proceedings, and codes of botanical nomenclature. Laws of Botanical Nomenclature. By Alphonse P. de Can- dolle, translated from the French by Dr. Weddell, Amer. Jour. Sci., 96: 63-77, 1868. This paper gives the so-called Paris Code in full, with editorial remarks. International Rules of Botanical Nomenclature. By John Bri- quet, Reporter General for the International Botanical Congress of Vienna, 1905, and Brussels, 1910. Second edition, 1912, unillustrated, Gustav Fischer, Jena. Written in three languages, French, English, and German, in one volume. The English section covers 19 pages and the entire work 110 pages, of which 29 are devoted to nomina conservanda in Latin, applicable to the three sections. American Code of Botanical Nomenclature. By the American Nomenclature Commission, Bui. Torrey Bot. Club., 34: 167-178, A 1907, unillustrated. brief statement of the reasons for advo- THE LITERATURE OF SYSTEMATIC BOTANY 313 eating the American Code as a substitute for the recently formulated International Rules, followed by the rules themselves. Type-basis Code of Botanical Nomenclature. By A. S. Hitchcock, U.S. Department of Agriculture, Science, 49 : 333330, 1919, unillustrated. The author, as chairman of a committee of the Botanical Society of America on generic types, here makes a brief report for the committee and records the rules recommended for adoption and known as the Type-basis Code. International Rules of Botanical Nomenclature. By John Bri- quet and A. B. Rendle of the Committee for Nomenclature for the 1930 Botanical Congress of Cambridge, 1935, Gustav Fischer, Jena. Written in three languages, English, French, and German, in one volume. The English section covers 26 pages exclusive of the nomina conservanda, etc. (20 pages). This work consists of an amplification of earlier rules. It includes the type concept and introduces the term "epithet" for the name of the species when it stands alone without the generic name. It is the most nearly complete code of International Rules of Nomenclature thus far published, lacking only the amendments authorized at the 1935 Congress of Amsterdam. Additions and Amendments to the International Rules of Botanical Nomenclature, Edition 3. By twelve botanists, Kew Roy. Bot. Gard. Bui Misc. Inform., No. 21932, pages 65-92. This is virtually a supplement to the International Rules as adopted by the 1930 International Congress at Cambridge. It embodies the work of the 1935 Congress at Amsterdam and the recommendations of committees authorized by that congress. It consists of minor changes in the rules, corrections, and decisions concerning the names of certain groups that were controversial. Conservation of Later Generic Homonyms. By Alfred Rehder et al.j Kew Roy. Bot. Gard. Bui. Misc. Inform., Nos. 6-9, 1935, pages 341-557. The subject matter is indicated in the title. Additional Nomina Generica Conservanda (Pteridophyta and Phanerogamae). By T. A. Sprague, Kew Roy. Bot. Gard. Bui. Misc. Inform. No. 3, 1940, pages 81-134. The subject matter is indicated in the title. Principal Decisions Concerning Nomenclature Adopted by the Sixth Botanical Congress at Amsterdam. By T. A. Sprague, Jour. Bot. [London], 74, 1936. This paper gives some of the most 314 A TEXTBOOK OF SYSTEMATIC BOTANY important work of the Amsterdam Congress in simpler form than the two publications cited above. Terminology of Types. By Donald Leslie Frizzell, Ainer. Midland Nat., 14: 637-668, 1933. This paper gives a brief dis- cussion of nomenclatural types of plants and animals, followed by an extensive list of the terms, both those in current use and others that are synonyms or obsolete, for the different kinds of types, with definitions. It has a good bibliography of previous papers on the subject. Types of Species in Botanical Taxonomy. By W. T. Swingle, A Science, 37: 864-867, 1913. discussion of the significance of type specimens, the value and care of such specimens, and the methods of reproducing, or duplicating for distribution to other herbaria, the one real type specimen. It gives a brief classi- fication of type materials, which is practically the same as that followed by botanists at the present time. It contains references to other papers on the same subject. WORLD FLORAS AND TAXONOMIC SYSTEMS A few great taxonomists have had the vision to construct systems of classification for great groups of plants, such as the Spermatophyta. Some of these have been published in skeleton form for the higher categories only; others have been carried down to the species. All but one of these taxonomic systems have been the products of European botanists. That of Charles E. Bessey is the work of an American and is based partly on the earlier publications of Europeans. All the systems now in use have had an evolutionary history and are not the product of any single botanist. % Genera Plantarum. By G. Bentham and J. D. Hooker, Kew, England. First edition, 1862-1883, three volumes, 3,577 pages, unillustrated; published by Reeve & Co., London. This monu- mental work gives a fairly complete classification of the higher plants with a definite system of categories and descriptions of all groups. The sequence is dicotyledons, gymnosperms, and mono- cotyledons. This work dominated the field of systematic botany more than any other prior to " Die nattirlichen Pflanzenfamilien," of Engler and Prantl. It used a system of categories somewhat different from that of today cohort for order and order for THE LITERATURE OF SYSTEMATIC BOTANY 315 family. Many consider the sequence of families to be more natural than that of Engler and Prantl. Die natttrlichen Pflanzenfamilien. By Adolph Engler, Berlin, and K. Prantl, Breslau. First edition, 1887-1909, second edition in preparation, eight volumes of which have been published to date. The largest work of its kind ever written, filling twentythree volumes and occupying several feet of shelf space. Pro- fusely illustrated; W. Engelmann, Leipzig. This great work covers the entire plant kingdom and is world-wide in its scope. It carries the classification to genera and in some cases to species, but there is considerable lack of uniformity in treatment owing to its composite authorship, many botanists having taken part in the preparation of the treatise. This publication has dominated the field of systematic botany since its publication. Most herbaria of the world and most botanical manuals follow its sequence of families. There is, however, at present a considerable breaking away from some of its phylogenetic conceptions. Syllabus der Pflanzenfamilien. By Adolph Engler and Ludwig Diele, University of Berlin. Eleventh edition, 1936, 419 pages and 476 illustrations; Gebriider Borntrager, Berlin. This book is usually thought of as a condensation of "Die natlirlichen Pflanzenfamilien. " It consists of an introduction on principles of classification, a list of families and higher categories according to the Engler system, and a brief discussion . of families and tribes. Handbuch der Systematischen Botanik. By Richard Wett- stein, University of Wien. Fourth edition, 1933-1935, two volumes, 1,152 pages, 709 plates, and 3,974 figures; Franz Deutickte, Leipzig. The great value of this work lies in its modern and original conceptions and its excellent descriptions and illustrations. The Classification of Flowering Plants. By A. B. Rendle, British Museum. Volume I, Gymnosperms and Monocoty- ledons. First edition, 1904, 403 pages and 187 illustrations. Volume II, Dicotyledons. First edition, 1925, 636 pages and 279 illustrations; Cambridge University Press. This work makes no pretense of listing all species but gives remarkably fine descriptions of all the families, the morphological tendencies within the families, and the modifications of the family types. It is par- ticularly strong in indicating the morphological equivalents of 316 A TEXTBOOK OF SYSTEMATIC BOTANY highly specialized organs. Examples are drawn from the flora of the entire world. The Families of Flowering Plants. By J. Hutchinson, Royal Botanic Gardens, Kew, England. Volume I, Dicotyledons. First edition, 1926, 328 pages and 264 illustrations, with an elaborate diagram of phylogenetic arrangement. Volume II, Monocotyledons. First edition, 1934, 243 pages and 107 illus- trations; Macmillan & Company, Ltd., London. Hutchinson's work represents the latest general exposition of the flowering plants. It is refreshing in its originality, with a number of progressive features: a statement of phylogenetic principles; a new phylogenetic scheme (reviewed on page 299) that is bound to provoke fruitful discussion; a grouping of the orders and families according to their characters, tendencies, and consequent affinities; an extensive key to families, world- wide in its scope; a concise and well-illustrated description of each family, accompanied in many instances by a distribution map. Flowers and Flowering Plants. By Raymond