Originally entitled The Naming of Plants and the Meanings of Plant Names, this book is in two parts. The first part has been written as an account of the way in which the naming of plants has changed with time and why the changes were necessary. It has not been the writer's intention to dwell upon the more fascinating aspects of common names but rather to progress from these to the situation which exists today, in which the botanical and horticultural names of plants must conform to internationally agreed standards. The aim has been to produce an interesting text which is equally as acceptable to the amateur gardener as to the botanist. The temptation to make this a definitive guide to the International Code of Botanical Nomenclature was resisted since others have done this already and with great clarity. A brief comment on synonymous and illegitimate botanical names and a reference to recent attempts to accommodate the various traits and interests in the naming of cultivated plants was added after the first edition.

The book had its origins in a collection of Latin plant names, and their meanings in English, which continued to grow by the year but which could never be complete. Not all plant names have meaningful translations. Some of the botanical literature gives full citation of plant names (and translations of the names, as well as common names).

It is basic to the collector's art to arrange items into groups. Postage stamps can be arranged by country of origin and then on face value, year of issue, design, colour variation or defects. The arranging process always resolves into a hierarchic set of groups. In the plant kingdom we have a descending hierarchy of groups through Divisions, divided into Classes, divided into Orders, divided into Families, divided into Genera, divided into Species. Subsidiary groupings are possible at each level of this hierarchy and are employed to rationalize the uniformity of relationships within the particular group. Thus, a genus may be divided into a mini-hierarchy of subgenera, divided into sections, divided into series in order to assort the components into groupings of close relatives. All such components would, nevertheless, be members of the one genus.

Early systems of classification were much less sophisticated and were based upon few aspects of plant structure, such as those which suggested signatures, and mainly upon ancient herbal and medicinal concepts. Later systems would reflect advances in man's comprehension of plant structure and function, and employ the morphology and anatomy of reproductive structures as defining features. Groupings such as Natural Orders and Genera had no precise limits or absolute parity, one with another; and genera are still very diverse in size, distribution and the extent to which they have been subdivided.

Man's highly developed constructive curiosity and his capacity for communication are two of the attributes distinguishing him from all other animals. Man alone has sought to understand the whole living world and things beyond his own environment and to pass his knowledge on to others. Consequently, when he discovers or invents something new he also creates a new word, or words, in order to be able to communicate his discovery or invention to others. There are no rules to govern the manner in which such new words are formed other than those of their acceptance and acceptability. This is equally true of the common, or vulgar or vernacular names of plants. Such names present few problems until communication becomes multilingual and the number of plants named becomes excessive. For example, the diuretic dandelion is easily accommodated in European languages. As the lion's tooth, it becomes Lowenzahn, dent de lion, dente di leone. As piss-abed it becomes pissenlit, piscacane, and piscialetto. When further study reveals that there are more than a thousand different kinds of dandelion throughout Europe, the formulation of common names for these is both difficult and unacceptable.

This book is intended for use by botanists, gardeners and others who have an interest in plant names, the manner and rules by which they are formed, their origins and their meanings. The evolution of our current taxonomic system, from its origins in classical Greece to its present situation, is dealt with in the first part. This presents an overview of some major aspects of resolving the earlier unregulated way of naming plants. It goes on to explain how the current system evolved, and the use of Latin as the universal, and often innovative, language for those names. It then treats the naming of cultivated plants, from the wild, produced by hybridization or by sporting, maintained only by vegetative means, in horticulture, agriculture or arboriculture, and perhaps differing only in single small features. These are subject to the botanical rules of nomenclature but also have their own set of international rules for the naming of garden variants. Both Codes (the International Code of Botanical Nomenclature and the International Code of Nomenclature for Cultivated Plants) are explained.

The main body of the book has been considerably enlarged for this edition. It consists of a glossary of over 17,000 names or components of names. Each entry contains an indication of the source from which the name is derived.

There can be no doubt that the diverse approaches to naming garden plants, by common names, by botanical names, by mixtures of botanical and common names, by group names and by fancy names, is no less complex than the former unregulated use of common or vernacular names. The psychology of advertising takes descriptive naming into yet new dimensions. It catches the eye with bargain offers of colourful, vigorous and hardy, large-headed, incurved Chrysanthemum cvs. by referring to them as HARDY FOOTBALL MUMS. Perhaps the director whose appointment was headlined ‘Football Mum appointed to Sainsburys’ hopes that she is also ‘hardy’. However, we are not here concerned with such colloquial names or the ethics of mail-order selling techniques but with the regulation of meaningful names under the Code.

In 1952, the Committee for the Nomenclature of Cultivated Plants of the International Botanical Congress and the International Horticultural Congress in London adopted the International Code of Nomenclature for Cultivated Plants. Sometimes known as the Cultivated Code, it was first published in 1953 and has been revised several times at irregular intervals since then (Trehane, 1995, Brickell et al., 2004). This Code formally introduced the term ‘cultivar’ to encompass all varieties or derivatives of wild plants which are raised under cultivation, and its aim is to ‘promote uniformity and fixity in the naming of agricultural, sylvicultural and horticultural cultivars (varieties)’. The term culton (plural culta) is also proposed as an equivalent of the botanical term taxon.

The rules which now govern the naming and the names of plants really had their beginnings in the views of Augustin P. de Candolle as he expressed them in his Théorie élémentaire de la botanique (1813). There, he advised that plants should have names in Latin (or Latin form but not compounded from different languages), formed according to the rules of Latin grammar and subject to the right of priority for the name given by the discoverer or the first describer. This advice was found inadequate and, in 1862, the International Botanical Congress in London adopted control over agreements on nomenclature. Alphonse Louise de Candolle (1806–1893) drew up four simple ‘Lois’, or laws, which were aimed at resolving what threatened to become a chaotic state of plant nomenclature. The Paris International Botanical Congress of 1867 adopted the Lois, which were:

1. One plant species shall have no more than one name.

2. No two plant species shall share the same name.

3. If a plant has two names, the name which is valid shall be that which was the earliest one to be published after 1753.

4. The author's name shall be cited, after the name of the plant, in order to establish the sense in which the name is used and its priority over other names.

Three centuries before Christ, Aristotle of Stagira (384–322 bc), disciple of Plato, wrote extensively and systematically of all that was then known of the physical and living world. In this monumental task, he laid the foundations of inductive reasoning. When he died, he left his writings and his teaching garden to one of his pupils, Theophrastus of Eresus (c. 370-287 bc), who also took over Aristotle's peripatetic school. Theophrastus' writings on mineralogy and plants totalled 22 treatises, of which nine books of Historia plantarum contain a collection of contemporary knowledge about plants and eight of De causis plantarum are a collection of his own critical observations, a departure from earlier philosophical approaches, and rightly entitle him to be regarded as the father of botany. These works were subsequently translated into Syrian, to Arabic, to Latin and back to Greek. He recognized the distinctions between monocotyledons and dicotyledons, superior and inferior ovaries in flowers, the necessity for pollination and the sexuality of plants but, although he used names for plants of beauty, use or oddity, he did not try to name everything. To the ancients, as to the people of earlier civilizations of Persia and China, plants were distinguished on the basis of their culinary, medicinal and decorative uses – as well as their supposed supernatural properties. For this reason, plants were given a name as well as a description.

The family is one of the ranks of the taxonomic system, as developed by plant taxonomists over the past two hundred years, that is important in the accurate identification of plants. In fact, it is the first stage (leaving aside the distinction between dicotyledons and monocotyledons) in the process of using the taxonomic hierarchy for the purposes of of identification. Identification means the finding of the correct name for an unknown plant, not as an end in itself, but as a means of access to all the information so far available about that plant. This is the primary purpose of the taxonomic system; later uses of this system, such as that purporting to show evolutionary relationships among the various taxa (phylogeny), are secondary and frequently not particularly helpful in the achieving of the primary aim.

In the flowering plants (Angiospermae), the number of families (often also called natural orders before 1905) was originally quite small (A. L. de Jussieu's Genera plantarum of 1789 contained exactly 100 families, although the precise significance of this number is not known), and the original idea was that all of the families could be known by a single person. Further developments in taxonomy, dependent on the increasing exploration of the world and its plants, showed that this small number was untenable and that more families would have to be recognised.

‘Spot’ characters are features that occur in relatively few families, thus rendering their identification simpler than tracing them through the actual key. Note that the appearance of a family name under a particular character does not mean that all members of that family show the feature in question.

Plants totally parasitic, without chlorophyll

51 Rafflesiaceae, 157 Cynomoriaceae, 168a Monotropaceae, 206 Orobanchaceae, 239a Burmanniaceae.

Plants clearly parasitic on the above-ground parts of other plants, with chlorophyll (excluding hemi-parasites)

14 Santalaceae, 15 Loranthaceae, 15a Viscaceae, 36 Lauraceae, 189 Convolvulaceae, 192 Lennoaceae.

Plants with bulbs

229 Liliaceae, 229k Hyacinthaceae, 229l Alliaceae, 232 Amaryllidaceae

Plants trapping insects by means of sticky hairs, pitchers or traps borne on stems or leaves, the remains of the insects usually digested

Pitchers: 63 Sarraceniaceae, 64 Nepenthaceae, 75 Cephalota-ceae. Active traps: 65 Droseraceae, 207 Lentibulariaceae. Sticky hairs: 22 Caryophyllaceae, 65 Droseraceae, 79 Byblidaceae, 80 Roridulaceae, 207 Lentibulariaceae.

Plants climbing by means of tendrils (coiling, often spring-like, much branched or bearing adhesive discs)

64 Nepenthaceae, 66a Fumariaceae, 84 Fabaceae, 107 Sapindaceae, 121 Vitaceae, 134 Passifloraceae, 144 Cucurbitaceae, 187a Cobaeaceae, 201 Bignoniaceae, 219 Compositae, 229 Liliaceae, 229s Smilacaceae.

Sap coloured or milky, not watery and translucent

Woody: 9 Eucommiaceae, 10 Moraceae, 94 Euphorbiaceae, 106 Aceraceae, 136 Bixaceae, 136a Cochlospermaceae, 158 Alangiaceae, 175 Sapotaceae. Herbaceous: 66 Papaveraceae, 94 Euphorbiaceae, 184 Apocynaceae, 185 Asclepiadaceae, 189 Convolvulaceae, 221a Limnocharitaceae, 248 Araceae.

This current book is a development of ideas put forward in the four published editions of The Identification of Flowering Plant Families (1965, 1979, 1989, 1997). The modest success of this book, and its persistence in print for such a long period, has led me to rewrite it completely, taking account of relatively recent developments in the recognition of flowering plant families.

Plant taxonomy is a free and unregulated subject, open to contributions from researchers and students of all kinds; because of this a vast range of opinions co-exist at any one time and to the casual observer the situation may appear chaotic. However, at any time there is a general, unregulated and undefined consensus as to what the taxonomic system should be. This consensus, which is expressed in the use of the various levels of the taxonomic hierarchy in Floras, revisions and other studies involving taxonomic practice, slowly changes in response to new ideas. Over the past 15 years, new ideas of what the family level means have become current: present-day authors are happy to recognise more groups as families than was the case 40 years ago, when the first edition of The Identification … was published.

The aim of the book is to provide a means of accurate identification of the flowering plant families native in north temperate regions, and to indicate how to proceed to identification of the genera and species; the assumption is made that the user has a general knowledge of plant structure, but is otherwise not particularly expert at identification or taxonomy.

In general, the variation given in the descriptions is somewhat wider than that presented in the key, and many characters used in the latter have had to be omitted. In using the descriptions, the following features must be assumed for most species of a family, unless otherwise stated: milky sap absent, habit not succulent, parts of the flower free from each other, stamens not antepetalous, and anthers opening by longitudinal slits. The ptyxis, as far as it is known, is given for each family: this refers to leaves if they are undivided, to leaflets if the leaves are divided.

The families are listed in the xorder of the Melchior system (see p. 3). No attempt has been made to group them into suprafamilial units (‘orders’), as these have no significance for practical identification.

The following points concerned with presentation should be noted.

Morphology

The oblique stroke (/) is used instead of ‘or’; the letter ‘n’ is used instead of ‘many’ or ‘numerous’ (i.e. more than 10 or 12). Abbreviations: K, calyx-segments or sepals; C, corolla-segments or petals; P, perianth-segments when these are undifferentiated; A, stamens; G, carpels. These letters are also used in the collective sense; for example, ‘A antepetalous’ means stamens antepetalous. Brackets are used to indicate that the segments of any particular whorl are united to each other; for example, C(5) means a corolla of 5 lobes united below into a cup or tube.