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01. Introduction to Principles & Practices


by George H. M. Lawrence, Professor of Botany at the Bailey Hortorium, Cornell University, 1951

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Contents of this page

TOC of the original book
01. Introduction


UKT notes
International Rules of Botanical Nomenclature

Contents of this page


Taxonomic botany is an advanced subject that deals not merely with the identification and naming of plants but also with their classification. Any approach to an understanding of plant taxonomy as thus broadly conceived requires considerable previous botanical training in related fields, especially those of morphology, anatomy, cytology, genetics, paleobotany, and geomorphology. [UKT ¶]

It cannot be presumed that every student may have the opportunity or time to acquire as a prerequisite even an elementary knowledge of these related sciences, nor should it be presumed that any single text need provide the material for such a background. However, any textbook devoted to the subject of taxonomic botany must make considerable use of the data available from these related topics, and must provide a sufficient explanation of their character and significance. [UKT ¶]

This book has been prepared as a text to meet these needs as required by beginning and intermediate students of systematic botany. Its level of presentation is sufficiently elementary not to presuppose formal training in all of the allied botanical sciences, yet it does open channels to further study of them by those more advanced students who may have had the benefit of a considerable botanical background.

This text represents several marked departures from existing works. The subject matter is divided formally into two parts. [UKT ¶]

Part One presents the more academic and theoretical considerations of taxonomy, supplemented by explanatory chapters of the practical fundamentals found to be essential to a minimum working knowledge of the science. [UKT ¶]

Part Two is composed of a systematic enumeration of the 264 families of vascular plants known to grow as indigens or exotics in North America north of Mexico, together with technical descriptions of each and pertinent discussions and other features as mentioned below. Supplementing this second part is an appendix providing an illustrated glossary of the botanical terms used throughout the text. [UKT ¶]

UKT addition: 121223, excerpt from: http://aob.oxfordjournals.org/content/83/3/271.abstract 121223
   "North America was geographically divided into twelve regions, which were latitudinally grouped into four zones, each with three regions, and longitudinally grouped into three zones, each with four regions. The native vascular flora of North America consists of 162 orders, 280 families, 1904 genera and 15352 species"
UKT note: Because the number of families have changed from 264 in Lawrence's time to 280 families at the present, we should be paying more attention to Part One.

The division of the text into these two parts is deliberate and has been effected in order to bring into one part (the first) those subjects that are topics of more detailed study and discussion, and from whose bibliographies may be made assigned readings. The separation of the treatment of the individual families into the second [{roman06}] part was effected in the recognition that ordinarily the student is assigned one or a few families for study at any one time and in a sequence that may not necessarily follow that of this text. Adoption of this view made it possible to set the treatment of the second part in a smaller type face, thereby permitting the inclusion of this relatively large number of families within a single volume. A second departure incorporated in Part Two is in the form of detailed discussions of the phylogenetic and related considerations of each family, together with bibliographies to the taxonomic, morphological, and cytogenetic literature pertinent to that family.

The text is an outgrowth of the author's experience as a research taxonomist and as a teacher. The first 8 chapters deal with the theoretical and basic principles prerequisite to a comprehension of the scope of the science, and to and ability to make intelligent use of its literature. [UKT ¶]

Chapter 09 provides an explanation of the subject of plant nomenclature, supported by an annotated abridgement of the rules by which it operates. This annotated abridgement of the rules has been found to be a necessary adjunct to laboratory exercises in most taxonomic work. Chapters 10 through 13 deal with the practical considerations attendant on field or herbarium studies, and serve as sources of basic information concerning procedures, techniques, and general curatorial problems. The last chapter of Part One comprises a considered and classified compilation of the literature of systematic botany, selected to indicate the scope of the literature and, by means of annotations, the particular use and reference value of the more significant aims that it includes. [UKT ¶]

The bibliographies terminating each chapter of Part One, and those at the close of the treatments of each family accounted for in Part Two, make no attempt to represent completeness and contain, for the most part, those references pertinent to American taxonomy and believed to be helpful to the student desiring to explore a particular phase of the subject beyond the limited scope of this text.

That the text may not be unreasonably provincial in its scope or range of usefulness, more families of plants are treated in Part Two than is usual. It is left to the instructor to select for detailed study, from this extensive enumeration, those families most pertinent to his particular needs. This treatment increase appreciably the utility of the text as a reference work and serves also to remind the student that that are many more families of vascular plants than the half hundred or so that may be studied in detail in the average taxonomy course. It may be of interest to [{roman07}] know that 87 per cent of the families treated in Part Two have representatives indigenous to or well established without cultivation in continental United States and that 70 per cent of the total contain indigens occuring within the limits of the Gray's Manual area.

The arrangements of the families follows that of Engler and Diels. The selection of this system is not because of any belief that it is the phylogenetically correct system, but rather because it is the only available system that has been devised to account in detail for the flora of the world. [UKT ¶]

Taxonomy is employed throughout the civilized world, and any system devised to meet the needs of those classifying plants must be adapted to studies of plants from the world viewpoint. Furthermore, the Engler system was selected because most current American floras and manuals are based on it, as also are all of the larger American herbaria. There are more recent systems of classifying plants that more closely approximate our current concepts of true relationships of vascular plants, but of the two currently receiving most favor one (that of Bessey) suffers currently from need of revision in the light of knowledge gained since 1915, and the other (that of Tippo) has been applied only to the larger units of classification of the world flora.

It will be noted in the second part of the text that neither floral diagrams nor formulas are provided. These devices do serve as aids in fixing family characteristics in the minds of some students and are available in existing taxonomy texts. It is believed that their use, and the degree of complexity to which they may be developed, is a matter to be left to the judgment of each instructor and not properly a component of a text of this character. The diagnostic drawings augmenting the descriptions of most families illustrate characteristic features of important members and serve as visual aids to instructor and student.

The illustrations and diagrams of Part One and of Appendix 2 have all been prepared especially for this work. Illustrations have been provided to show diagnostic and technical characters of each of the 264 families treated in Part Two, and are represented by 263 figures. Of this number, 179 have been made available through the generosity of the author and the publisher of Bailey's Manual, and are figures that had been prepared earlier for that work under my direction. The balance of the figures have been drawn since then for this text.

The glossary, comprising Appendix 2, has been adapted from that in Baily's Manual of cultivated plants (ed. 2, 1949) subject to modifications, amplifications, and a few corrections. The attempt has been made to account for every term employed in this text. Terms considered essential [{roman08}] to the working vocabulary of beginning students are preceded by an asterisk, and the majority of these terms are illustrated in the figures accompany the glossary.

In preparing descriptions of plant families, effort has been made to insure that characteristics of comparable structure of broadly related families are given and in this way the critical comparisons of such structures between these families are made possible. Like most introductory texts, little or no new and original material is presented in either Parts One or Two, it being especially true of taxonomy that before the complexities of advanced systematics can be assimilated effectively, the basic fundamentals, concepts, and working vocabulary must be mastered.

In the preparation of the chapters of Part One, assistance has been enlisted of and freely given by a number of renowned authorities. The manuscript copy of Part One has been read by Dr. R. C. Rollins, Director of the Gray Herbarium, Harvard University and by Dr. J. M. Fogg, Jr., Vice Provost, University of Pennsylvania, each of whom made many helpful criticisms and suggestions. That of the first 5 chapters was read critically by Professor A. J. Eames of Cornell University; Chapter 5 on phylogeny by Dr. W. B. Turrill, Keeper of the Herbarium, Royal Botanic Gardens, Kew; Chapter 8 on biosystematics by Dr. H. G. Baker, University of Leeds, by the trio of Drs. Jens Clausen, David Keek, and William Hiesey of Carnegie Institution of Washington, and by Professor H. H. Smith of Cornell University; proof of Chapter 9 on nomenclature was read in manuscript by Dr. T. A. Sprague and in proof by Professor J. Lanjouw; and Chapter 14 on taxonomic literature by W. T. Stearn, Librarian, Lindley Library, London. Proof of this chapter was read by Dr. A. Becherer, Conservatoire de Botanique, Geneva, well known for his knowledge of European botanical literature. From each of these, many valuable suggestions have been received and I gratefully acknowledge their assistance and express my sincere thanks for their their generosity and helpfulness. [UKT ¶]

The treatments of many of the families of Part Two have been read critically by botanists who have monographed or made special studies of them and these include (together with the families reviewed): Abbe, E. C. (Betulaceae, Fagaceae, Leitneriaceae); Allen, C. K. (Lauraceae); Baily, L. H. (Palmae); Ball, C. R. (Salicaceae); Benson, L. (Ranunculaceae); Camp, W. H. (Ericaceae); Clausen, R. T. (Crassulaceae); Clover, E. (Cactaceae); Constance, L. (Hydrophyllaceae, Umbelliferae); Cowan, R. S. (Rutaceae); Cronquist, A. (Compositae, Sapindaceae, Simbaroubaceae); Cutler, H. C. (Ephedraceae); Dillon, G. and Schweinfurth, C. (Orchidaceae); Epling, C. (Labiatae); Fassett.,  [{roman09}] N. C. (Podostemaceae); Foster, R. C. (Iridaceae); Gleason, H. A. (Melastomaceae); Holm, R. W. (Asclepiadaceae); Johnston, I. M. (Boraginaceae); Kearney, T. H. (Malvaceae); Kobuski, C. E. (Theaceae); Laubengayer, R. A. (Polygonaceae); Leonard, F. C. (Acanthaceae); McVaugh, R. (Campanulaceae); Maguire, B. (Caryophyllaceae, Guttiferae, Hypericaccac); Manning, W. E. (Juglandaceae); Mason, H. L. (Polemoniaceae); Moldenke, H. N. (Eriocaulaceae, Verbenaceae); Moore, H. E. Jr. (Amaryllidaceae, Commelinaceae, Geraniaceae); Morton, C. V. (Gesneriaceae, Solanaceae); Moseley, M. F. Jr. (Casuarinaceae); Munz, P. A. (Hydrocaryaceae, Onagraceae); Pennell, F. (Scrophulariaceae); Perry, L. M. (Myrtaceae); Rollins, R. C. (Cruciferae); Smith, A. C. (Araliaceae, Cereidiphyllaceae, Eupteleaceae, Hippocrataceae, Illiciaceae, Magnoliaceae, Myristicaceae, Schisandraceae, Tetracentraceae, Trochodendraceae); Smith, F. N. (Santalaceae); Smith, L. B. (Bromeliaceae); Swallen, J. R. (Gramineae); Tippo, O. (Eucommiaceae, Urticales); Tryon, R. M. (Pteridophyta); Uhl, C. H. (Crassulaceae); Uhl, N. W. (Helobiae); Wheeler, L. C. (Euphorbiaceae); Woodson, R. E. Jr. (Apocynaceae, Asclepiadaceae).

To each of these authorities of special interests I acknowledge freely the very material assistance received, and while most or all of their constructive criticisms were incorporated in the respective treatments, I assume full responsibility for the presentation in this text. [UKT ¶]

In addition to these, I wish to acknowledge the cooperation of the botanical illustrator, Miss Marion E. Ruff, whose meticulous care and skill are reflected in the drawings prepared by her. Material assistance and encouragement have been received from my associates at the Bailey Hortorium, notably W. J. Dress, H. E. More Jr., E. Z. Bailey, and L. H. Bailey, to all of whom I express my sincere thanks and appreciation for their friendly cooperation. Numerous other botanists have been consulted on many aspects of material incorporated in this text and have been most generous in their response. To each of them I express my gratitude for their helpful opinions and counsel. Revised drafts of the manuscript were typed by my wife, Miriam B. Lawrence, without whose patience and understanding this book would not have been completed.

G. H. M. L.

Ithaca, N.Y.
July, 1951

Contents of this page

Table of Contents of the original book

Part One: Principles and Practices of Plant Taxonomy


01. Introduction, p.003

02. Taxonomy and its Significance, p.006
Interrelationships with allied science; problems in taxonomy; opportunities.

03. History of Classification, p.013
Period 1 - classifications based on habit;
Period 2 - artificial systems base on numerical classifications;
Period 3 - systems based on form relationships
Period 4 - systems based on phylogeny; other contemporary systems.

04. Principles of Taxonomy, p.042 [UKT: I have split up Lawrence's chapter 04 into two. The first part dealing with categories is not very useful to me, whereas the second part is more useful because it deals more with identification of a plant in the wild -- more helpful to a layperson collecting plants.]
Major categories of classification; minor categories of classification; infra-specific categories; morphological criteria.

05. Phylogenetic Considerations, p.092
Significance to taxonomy; diversity of phyletic concepts; contributions to phylogenetic knowledge; phylogeny and the higher categories.

06. Current Systems of Classification, p.114
Bentham and Hooker; Engler and Prantl; Rendle; Wettstein; Pulle; Skottsberg; Bessey; Hallier; Hutchinson. [{roman12}]

07. The Geography of Vascular Plants, p.141
Genesis and evolution; geography and its relationship to plant distribution; vegetatioin areas of the earth; physiographic areas of North America; taxonomic significance of physiographic areas; phytogeography -- static vs. dynamic; principles of dynamic geography; importance of phytogeography to taxonomy.

08. Biosystematics and Cytogenetics, p.169
Biosystematics and modern taxonomy; mechanics of evolution; biosystematic categories; methods in experimental taxonomy; importance to taxonomic research and interpretation; apomixis; limitations of cytogenetic criteria.

09. Plant Nomenclature, p.192
Beginnings of organized nomenclature; codes of nomenclature -- Paris, Rochester, Vienna, American; International Rules of Botanical Nomenclature; primary and other provisions of the Rules; units of classification.

10. Plant Identification, p.223
Taxonomic literature; herbaria.

11. Field and Herbarium Techniques, p.234
Collecting procedures; preparation of specimens; preservation of specimens; housing of bulky materials; herbarium cases; type specimens.

12. Monographs and Revisions, p.263

13. Floristics, p.275
Types of floristic study; procedures.

14. Literature of Taxonomic Botany, p.284
General taxonomic indexes; world floras; regional floras and manuals; monographs and revisions; bibliographies, catalogues, and review serials; periodicals; glossaries and dictionaries; cultivated and economic plants; maps and cartography; miscellaneous reference works.

Part Two: Selected Families of Vascular Plants

Introduction, p.333
Pteridophyta, p.334
Embryophyta Siphonogama, p.354
  Gymnospermae, p.355
  Angiospermae, p.370
    Monocotyledoneae, p.371
    Dicotyledoneae, p.438

Appendix 1
Suggested syllabus for elementary course, p.733

Appendix 2
Illustrated glossary of botanical terms, p.737
Index, p.777

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01. Introduction to Principles and Practices

Taxonomy is a science that includes identification, nomenclature, and classification of objects, and is usually restricted to objects of biological origin; when limited to plants, it is often referred to as systematic botany. In this text the taxonomy of vascular plants includes the systematics of the taxa ( fn003-01) known as pteridophytes, gymnosperms, and angiosperms. [UKT ¶]

Taxonomy, as a biological science, has been defined variously by leading authorities, and the above statement is not to be construed as a formal definition but rather as an indication of the scope of the subject. [UKT ¶]

Some earlier botanists restricted the term taxonomy to account for the principles underlying a system of classification. In contrast, systematics was treated by them as pertaining to the classification of plants within a particular nomenclatural system. There may be valid cause for recognizing these distinctions in concept, but if they were to be accepted there would remain the need for a single collective term to account for the several functions represented by identification, nomenclature, and classification. A plant taxonomist is recognized universally as one who identifies, names, and classifies plants; taxonomy as a workable term must likewise embrace these same functions.

The terms taxonomy and systematic botany are used interchangeably throughout this text. [UKT ¶]

Plant taxonomy as a science is treated in its orthodox sense, that is, a science based fundamentally on morphology with the support of all interrelated sciences. This text treats descriptive taxonomy largely as of historical interest and, while recognizing the biological objectivity of the newer systematics and the potentials of their goals, accepts their tenets only in so far as they are compatible with the objectives outlined below.

Identification is the determination of a taxon as being identical with or similar to another and already known element; the determination may or may not be arrived at by the aid of literature or by comparison with [{p004}] plants of known identity. [UKT ¶]

In some instances, the plant may be determined to be new to science, a situation that results after elimination of the possibilities of its being like any known element. No names need be involved in the process of identifying a plant. For example, suppose that three related plants are at hand and are determined to represent three separate species; then suppose that a fourth plant of the same relationships comes to hand and by examination is found to be similar to the second of the first three; the recognition of this fourth plant as similar to another is its identification -- the new plant has been identified as being like another known plant.

Nomenclature is concerned with the determination of the correct name of a known plant according to a nomenclatural system. [UKT ¶]

Once the plant has been identified it becomes necessary that it have a scientific name that, in effect, it may have a handle by which to be designated. The naming of plants is a subject of international importance. It is a function of taxonomy that is regulated by what are known as the International Rules of Botanical Nomenclature. These rules direct the procedures to be followed for the determination of the name to be applied to a particular plant, or to be followed in situations requiring the selection of a name for a new plant.

Classification is the placing of a plant (or group of plants) in groups or categories according to a particular plan or sequence and in conformity with a nomenclatural system. Every species is classified as a member of a particular genus, every genus belongs to a particular family, the family to an order, the order to a class, and so on. [UKT ¶]

In actual practice, classification deals more with the placing of a plant group in its proper place within the selected schema than the placing of an individual plant in one of several minor categories. The theory of evolution postulates that plants now living are descendants of ancestral types; this means that there are genetical relationships of all degrees of proximity among living plants just as there are similar relationships among vertebrate and other animals. [UKT ¶]

The principles of modern plant classification recognize that these relationships exist, and these principles have been formulated in an attempt to bring related plant groups together in so far as knowledge of them permits. This knowledge, assembled for the purpose of arriving at a satisfactory classification, must be drawn from all available sources -- many of which are beyond the limits of taxonomy. [UKT ¶]

Among these sources are those phases of science that deal with plant morphology, anatomy, cytology, genetics, paleobotany, phytogeography, ecology, geomorphology, and biochemistry (serology). If a plant is a variant of a species, it [{p005}] is not difficult to determine the species with which it is affiliated. However, the higher the category, the greater is the difficulty of determining the relationship of its components to other taxa of the same level, and the problems of classification becomes increasingly complex. [UKT ¶]

In ordinary practice, categories above that of the family are seldom considered in taxonomic studies of plant relationships (classification). The classification of the higher as well as the lower categories is a subject somewhat apart from taxonomy in the descriptive or classical sense, but by modern concepts is closely integrated with it. [UKT ¶]

The classification of taxa is called phylogeny. The main interests of phylogenetic studies are the composition, disposition, and classification of taxa especially in the categories of family, order, class, and larger groups. The results of such studies are of vital importance to the taxonomist. The significance of phylogeny is receiving increasing attention by most taxonomists, and greater recognition is being given to it especially at the lower levels of classification.

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fn003-01. Explanation and discussion of the terms taxon and taxa are provided on p. 53.
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UKT notes

Alpha taxonomy

From Wikipedia: http://en.wikipedia.org/wiki/Alpha_taxonomy 121230

Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. [1] This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and botanical gardens.

The term "alpha" refers to alpha taxonomy being the first and most basic step in taxonomy.

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angiosperm n. 1. A plant whose ovules are enclosed in an ovary; a flowering plant. -- AHTD

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Folk taxonomy

From Wikipedia: http://en.wikipedia.org/wiki/Folk_taxonomy 121230

A folk taxonomy is a vernacular naming system, and can be contrasted with scientific taxonomy. Folk biological classification is the way peoples describe and organize their natural surroundings/ the world around them, typically making generous use of form taxa like "shrubs", "bugs", "ducks", " ungulates" and the likes. [UKT ¶]

Astrology is a folk taxonomy, while astronomy uses a scientific classification system, although both involve observations of the stars and celestial bodies and both terms seem equally scientific, with the former meaning "the teachings about the stars" and the latter "the rules about the stars". Folk taxonomies are generated from social knowledge and are used in everyday speech. They are distinguished from scientific taxonomies that claim to be disembedded from social relations and thus objective and universal.

Anthropologists have observed that taxonomies are generally embedded in local cultural and social systems, and serve various social functions. Arguably, the most well-known and influential study of folk taxonomies is Émile Durkheim's The Elementary Forms of Religious Life.

Folk taxonomies exist to allow popular identification of classes of objects, and apply to all areas of human activity. All parts of the world have their own systems of naming local plants and animals. These naming systems are a vital aid to survival and include information such as the fruiting patterns of trees and the habits of large mammals. These localised naming systems are folk taxonomies. Theophrastus recorded evidence of a Greek folk taxonomy for plants, but later formalized botanical taxonomies were laid out in the 18th century by Carolus Linnaeus.

Critics of the concept of "race" in humans argue that race is a folk taxonomy rather than a scientific classification. [1]

Scientists generally recognize that folk taxonomies conflict at times with Linnaean taxonomy or current interpretations of evolutionary relationships, and can tend to refer to generalized rather than quantitatively informative traits in an organism.

Notable folk taxa include Saber-toothed cat.

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gymnosperm n. 1. A plant, such as a cycad or conifer, whose seeds are not enclosed within an ovary. [From New Latin Gymnospermaeclass name from Greek gumnospermos gumnos naked] -- AHTD

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International Rules of Botanical Nomenclature

From Wikipedia: http://en.wikipedia.org/wiki/Botanical_nomenclature 121223

Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this process. The starting point for modern botanical nomenclature is Linnaeus' Species Plantarum of 1753. Botanical nomenclature is governed by the International Code of Nomenclature for algae, fungi, and plants (ICN), which replaces the International Code of Botanical Nomenclature (ICBN).

UKT: More in the Wikipedia article.

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From Wikipedia: http://en.wikipedia.org/wiki/Phylogenetics 121223

In biology, phylogenetics is the study of evolutionary relationships among groups of organisms (e.g. species, populations), which are discovered through molecular sequencing data and morphological data matrices. The term phylogenetics derives from the Greek terms phylé (φυλή) and phylon (φῦλον), denoting "tribe", "clan", "race" [1] and the adjectival form, genetikós (γενετικός), of the word genesis (γένεσις) "origin," "source," "birth".[2] The result of phylogenetic studies is a hypothesis about the evolutionary history of taxonomic groups: their phylogeny. [3]

Evolution is regarded as a branching process, whereby populations are altered over time and may split into separate branches, hybridize together, or terminate by extinction. This may be visualized in a phylogenetic tree, a hypothesis of the order in which evolutionary events are assumed to have occurred.

Phylogenetic analyses have become essential in researching the evolutionary tree of life. The overall goal of National Science Foundation's Assembling the Tree of Life activity (AToL) is to resolve evolutionary relationships for large groups of organisms throughout the history of life, with the research often involving large teams working across institutions and disciplines. Investigators are typically supported for projects in data acquisition, analysis, algorithm development and dissemination in computational phylogenetics and phyloinformatics. For example, RedToL aims at reconstructing the Red Algal Tree of Life.

Taxonomy, the classification, identification, and naming of organisms, is usually richly informed by phylogenetics, but remains methodologically and logically distinct. [4] The degree to which taxonomy depends on phylogenies differs between schools of taxonomy: numerical taxonomy ignored phylogeny altogether, trying to represent the similarity between organisms instead; phylogenetic systematics tries to reproduce phylogeny in its classification without loss of information; evolutionary taxonomy tries to find a compromise between them in order to represent stages of evolution

UKT: More in the Wikipedia article

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pteridophyte n. 1. Any of various vascular plants that reproduce by means of spores rather than by seeds, including the ferns and related plants, such as club mosses and horsetails. [From New Latin Pteridophyta former division name Greek pteris pterid-fern] -- AHTD

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tax·on n. pl. ta·xa   Biology  1. A taxonomic category or group, such as a phylum, order, family, genus, or species. [New Latin back-formation from taxonomy] -- AHTD

From Wikipedia: http://en.wikipedia.org/wiki/Taxon 121230

A taxon (plural: taxa) is a group of one (or more) populations of organism(s), which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement. Defining what belongs or does not belong to such a taxonomic group is done by a taxonomist with the science of taxonomy. It is not uncommon for one taxonomist to disagree with another on what exactly belongs to a taxon, or on what exact criteria should be used for inclusion.

Taxonomists sometimes make a distinction between "good" (or natural) taxa and others that are "not good" (or artificial). Today it is common to define a good taxon as one that reflects evolutionary ( phylogenetic) relationships, but this is not mandatory.

A taxon may be given a formal scientific name, the application of which is governed by one of the Nomenclature Codes, which set out rules to determine which scientific name is correct for that particular grouping.

Advocates of phylogenetic nomenclature, using cladistic methods, require taxa to be monophyletic, consisting of all descendants of some ancestor. They generally do not refer to taxa as their basic unit, but to " clades," a clade being a special form of taxon. However, even in traditional nomenclature, few taxonomists of our time would establish new taxa that they know to be paraphyletic. [1] A famous example of a widely accepted taxon that is not also a clade is the " Reptilia."

UKT: The term "paraphyletic" from "paraphyly" is also used in historical linguistics. See Wikipedia:
#1. http://en.wikipedia.org/wiki/Paraphyletic 121230
#2. http://en.wikipedia.org/wiki/Tree_model 121230
The following is taken from #1.
   "The concept of paraphyly has also been applied to historical linguistics, where the methods of cladistics have found some utility in comparing languages. For instance, the Formosan languages form a paraphyletic group of the Austronesian languages as the term refers to the nine branches of the Austronesian family that are not Malayo-Polynesian and restricted to the island of Taiwan. [17]

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