NAMING, IDENTIFICATION AND CLASSIFICATION
There are two aspects to ‘naming’: the generation of the name and the application of the name. Application of a name, better called ‘identification’, is a subject we take up in Chapter 5. Before anything can be identified, however, the names must be generated.
Names may be applied to specific elements, such as a person, or to vaguer, more abstract things, such as a football team (whose players change with time). Plant names are of the second, abstract type, although one name is, of course, in practice applicable to all individual plants of a particular type, unlike members of a football team.
Names might be generated in a moment of creation or evolve gradually. The origin of ‘common’ plant names is mostly a matter of gradual evolution in the language.
62 Plant Identification
Source: Department of Plant Sciences, Oxford University Figure 4.1 Illustration from the Grete Herbal of 1526, an era when botany had not acquired a great deal of scientific rigour
Although the scientific names accepted for particular plants change from time to time, scientific naming involves sudden name creation, deliberately divorced from the gradual evolution of the vernacular, and partly for this reason plant naming makes heavy use of the dead languages of Latin and ancient Greek. It is the job of the taxonomist to create scientific names, to link these to specimens in herbaria and to describe their features in a way that will distinguish them from all plants named previously. The field guide writer has to sort out how to apply these names to plants on a daily basis, out in the field, and how they relate to common names (see Box 4.1).
Scientists strive to give a single name to all different types of plants so that they can be referred to in a standard way. They find common plant names unreliable for general use for various reasons:
•
One name, several species: a common name may be ambiguous, with the same one used for different plants in different places – such as ‘iron-wood’ or ‘cherry’. Trade names particularly cover products of a range of plant species with similar properties
– for example, timber trade names often address timber qualities, not the details of the living tree (‘mahogany’ applies to several species from around the tropics). The common name ‘Madeira’ is an extreme example, used now for a limited number of timber trees in parts of the Caribbean, but derived from the Spanish ‘madera’, or timber in general. Ambiguity also arises where colonists, finding substitutes for familiar plants from their old home, use their old names for the new species. So, we find multiple, unrelated verbenas, cherries, plums and walnuts in Anglophone tropical countries.
Plant names and botanical publication 63
BOX 4.1 TYPES OF NON-SCIENTIFIC NAMES
There is wide overlap between the following; but it is useful to be as precise as possible when defining what non-scientific names to include in your field guide. It is a good idea to choose a particular non-italic font for these, to contrast with the italic convention of scientific names:
•
Common name: any non-scientific, commonly used name, without regard to linguistics and not necessarily ‘local’ – for example, ‘coconut’ and ‘gum Arabic tree’. All of the following names are types of common names; but it is better to use a more particular term from the list below, if possible.
•
Vernacular name: name explicitly in a particular (generally non-global) language or dialect, usually with language specified – for example, Acacia nilotica = ‘ ol-erbat’
(Masai) or ‘chigundigundi’ (Digo).
•
Folk name: like vernacular name, but resonating with ‘folklore’ – that is, hint of being a name with a long tradition of use, and not necessarily a particular language, for example, Senecio vulgaris = ‘groundsel’ in the UK, from the Anglo-Saxon
‘grundswelge’ (‘swelgan’, to swallow; ‘grund’, ground), because it grows very quickly.
•
Local name: any of the above, but emphasizing what people in a limited region commonly use.
•
Trade name: transcultural names used in markets, especially international ones – for example, ‘African mahogany’, ‘kola’, ‘iroko’ and often applying more to a product than the tree, such as the gum of Acacia nilotica = gum Arabic.
•
Incompleteness: it frequently happens that a species is not just merged with others in some generic common name, but is effectively invisible in the local culture, addressed by terms such as ‘tree’, ‘bois-cendre’ or local names that translate as ‘I don’t know’.
•
Many names, one species: several different names apply to what scientists consider the same type of plant. This is usually the case for widespread species, where there are many vernacular names, and for very useful species, where the different names may strictly apply to a particular aspect of the plant. People migrate and the origin of functional names are forgotten, so even in one village you may well find disagreement on the most correct local name for a plant.
•
Impermanence: folk names tend to disappear or evolve, often even in a few years, with the culture that invented them. They may also be supplanted wholesale, hence the Victorian move to clean up the common names of British plants, when ‘pilewort’
and ‘pissabed’ were replaced with lesser ‘celandine’ and ‘dandelion’. There is no guarantee that a local name will continue to be used for the same plant (see Case studies 4.1 and 4.2).
What is less often emphasized, however, is that scientific names suffer from all of these same types of problem – impermanence, incompleteness, synonymy and inconsistency of application (see Case study 4.3) – albeit usually in a less chronic form. This is in spite of efforts made by scientists to place their names beyond the vagaries of normal language in the ways we summarize next.
64 Plant Identification
CASE STUDY 4.1 SHIFTING LOCAL NAMES
FOR THE RATTANS OF LAOS
Each of the local names given in A Field Guide to the Rattans of Lao PDR (Evans, 2001) was used by local people for a specimen we collected. Although these names are often used consistently in a particular village, they vary endlessly from village to village. To pick just a few examples, ‘wai namleuang’ (yellow spine rattan) is used for at least six species, ‘wai hangnou’ (rat-tail rattan) is used for at least four species and ‘wai thoon’, a name usually applied to the very distinctive and valuable Calamus poilanei, is used for at least two other large but commercially worthless species, C. flagellum and Plectocomia spp., in areas where C. poilanei apparently does not occur. In Vientiane Province in Laos, the name ‘wai nyair’ is used for both C. viminalis and C. tenuis by different people; but getting these two mixed up when you start a plantation could be a disaster – one likes dry ground, the other, flooding.
The reason for this confusing situation is simple – local names only need to distinguish the 5 to 15 species that might occur in the limited area used by a few neighbouring villages.
It doesn’t matter to these users if the same name is used for another species elsewhere.
But it does matter to us, working across the whole country. So, be very sceptical with lists of local names, particularly when they have been compiled for a different region or ethnic group.
Source: Evans (2001)
Scientific names
Scientific names reflect the hierarchy in which species are classified (see Box 4.2). This hierarchical arrangement is also a typical, though not universal, feature of common nomenclature: combinations of names to express patterns of affinity or perceived relat-edness in plants (tree, palm tree, coconut palm tree, dwarf coconut palm tree), rather like street addresses. Such a hierarchical classification in taxonomy helps the identification process by allowing identifiers to think, perhaps, first of the family, then of the genus, then the species, even if only the latter two ranks are routinely stated. A hierarchical arrangement of plant names or classes (‘t
axa’) also helps scientists to organize their descriptive data. Descriptions of species in a particular book do not have to repeat the general details about its genus or family.
Publication of species names
Although some early botanical literature – notably Linnaeus’s Species Plantarum (1753)
– involved massive syntheses of known and new plant names, or were catalogues of useful plants, nowadays new species names are often published a few at a time in journals, or sometimes in the other types of botanical publications. Scientific plant names have to be published formally, implying copies in publicly available, printed media. Unfortunately, this does not mean that all species descriptions are easily available throughout the world, even in the age of the internet.
The most useful reference for any plant name, though, is an actual specimen of a plant (see Box 4.3). When published, a ‘type specimen’ is deposited in a herbarium and a short description, in Latin, has to appear in a journal referring to the type specimen and
Plant names and botanical publication 65
CASE STUDY 4.2 THE LAW AND SAPOTACEAE NAMES IN GHANA Tree species in the family Sapotaceae in Ghana are economically important; but there is confusion about their names. Several different species are routinely called akasa, adasema, kumfena and asanfena, although the Forestry Department has tried to standardize the application of these names to Chrysophyllum abidum, C. subnudum, C. giganteum and Pouteria spp., respectively. It is a constant challenge to ensure that in tree inventories, these local names are applied consistently (Latin names are too long and complicated to be recorded on inventory field forms). The timber from the trees differs in value and, conse-quently, royalty rates; timber concessionaires have to pay according to names assigned during stock enumerations before logging.
Some of the confusion arises because people notice no difference between the trees of these various species, with their fibrous, latex-producing bark, and discoloured crowns: this represents a simple mistake, but there is a deeper reason. Akasa is a fruit name applied originally, and in many peoples’ minds, to the tasty fruit of C. albidum, which is often planted. However, the discoloured foliage and other aspects of the C. albidum tree are very similar to those of the C. giganteum tree (supposedly kumfena), and there is a strong tendency for people to call the latter akasa, as well, although the edible fruit is a different shape and smaller. Disagreements arise frequently because it is not strictly wrong in the vernacular sense for people to call both species akasa, or one of the species akasa and kumfena on different occasions; it is only wrong in the trade name sense, especially as C. giganteum is a timber tree with a higher royalty than C. albidum. During recent years, there have been legal proceedings in local forest offices because it appeared, apparently incorrectly, that the local timber company had deliberately misapplied local names to save many thousands of dollars in royalties. To further complicate matters, it was found after closer scrutiny of the C. giganteum plants during emergency training sessions that the relevant C. giganteum population in one forest was a local variant of the species, with several slight differences from the rest of the species, a fact not reflected in the available literature.
Notice how important the presence of the standard scientific name was to try and establish any order in the above situation. However, during the 1990s a monograph of the Sapotaceae was published that changed overnight the scientific names for African Aningeria into the pan-tropical Pouteria. At that time, perplexed timber traders were still able to say: ‘What is Pouteria? Oh, you mean asanfena.’ In other words, the local name was more widely understood and less confusing at that time than the scientific name.
So, by all means try helping to standardize local names for use in technical contexts; but expect the tide of common use to run against you. Generally, applied local names and current scientific names are appreciated by different audiences, and can function in a ‘belt-and-braces’ way to establish plant identity.
giving it the name (see Box 4.4). This and other rules of taxonomy are outlined in the International Code of Botanical Nomenclature (International Association for Plant taxonomy, 2000). Winston (1999) provides a friendly synopsis and a useful guide to the whole task of naming a species. Obtaining original descriptions and type specimens are major hurdles and expenses to taxonomy, and will normally involve you or a colleague working in a well-resourced botanic institution.
The only plant, without question, that has a particular name is the individual plant from which the type specimen was clipped. Botanists use these type specimens as reference beacons in the spectrum of plant life. Anything that looks sufficiently similar to the
66 Plant Identification
CASE STUDY 4.3 SCIENTIFIC NAMES IN THE TREE FLORA OF MALAYA Corner (1988) describes the common experience of shifting sands of taxonomy regarding the updated version of his Wayside Trees of Malaya: Botanists have been able to visit and study critical collections in other countries for which, previously, there was neither opportunity nor funds. Not least, perhaps, there have been such improvements in postal services that the old and precious specimens – the type specimens on which names depend – can be borrowed. In tropical Asia there had grown up three tradi-tions: the British was based on collections based in London and Edinburgh; the Dutch on collections at Leiden and Utrecht; and the French on collections in Paris. Many a plant, in consequence, had three names, and more according to the country where it had been studied … using the publications of Flora Malesiana , we have had to alter the names of more than 200 species of trees in this revision. Finality is not in sight because several large families await revision, and the concepts of species and genus are still fluid.
The 200 new species names referred to had arisen for a total of 950 species, almost 20 per cent in about 40 years, or 0.5 per cent a year. None of the local names were changed between the same editions.
Source: Corner (1988)
BOX 4.2 SCIENTIFIC SPECIES, BINOMIALS, INFRA-SPECIFIC
NAMES AND AUTHORS
The basic unit of scientific naming is the species – the group of all plants that look more or less the same as each other, apart from variation due to age, gender and environmentally induced differences, and that are capable of interbreeding. We will assume our readers have a basic idea of a species, but see Winston (1999) for further discussion. The scientific name for species, a binomial, always has two parts, comprising the genus, then the
‘species epithet’, such as Melia azedarach, where the species epithet is azedarach. In formal publications, the author (the person who formally published the original name, usually abbreviated) is indicated, as well. Usually the genus and species names are itali-cized, while the author is not – for example, Melia azedarach Linnaeus or Melia azedarach L. This is the scientific name that Linnaeus invented for the Persian lilac. The author might be mentioned because it has often happened, particularly with scientific names invented a long time ago, that the same name has been used for different plants – for example, the name Psychotria albicaulis has been used twice, by two authors (Valeton and Scott-Elliot) for different species. To distinguish these two uses, one is properly P. albicaulis Valeton and the other is P. albicaulis Scott-Elliot: only one name is allowed to be in use; but the other meaning of the name still has to be referred to by taxonomists. Furthermore, the author name gives some clues about the age and origin of the names.
Some species are subdivided and given extra names to represent local or minor variants; these so-called infra-specific names, including subspecies, varieties or forms, can then be specified after the normal species name – for example, Antiaris toxicaria subspp.
toxicaria, with or without the authors. Unfortunately, many of the tools for looking up species names are incomplete for these infra-specific taxa.
Plant names and botanical publication 67
BOX 4.3 THE IMPORTANCE AND METHOD OF COLLECTING
HERBARIUM SPECIMENS
We have seen that plant names are originally based on specimens dep
osited in herbaria.
Taxonomic work relies on them absolutely. However, subsequent identification of plants also relies to a great extent on specimens, and do not expect that a field guide will completely remove the need to collect specimens in the tropical rainforest if the names are to be as accurate as possible and scientifically respectable. You certainly should collect specimens as part of the work towards all but the least technical field guide. The well-stored specimen provides a permanent record of a name used – for instance, in a scientific publication or for a published photograph, which can be consulted much later, perhaps when the forest in question has been cleared and names have changed. For more information on specimen collection, visit your local herbarium or see Bridson et al (1995).
type specimen is then identified with that name, and, of course, the meaning of ‘sufficiently similar’ is the basis of much taxonomic debate. It surprises even some regular users of scientific names that they are open to interpretation and, therefore, in practice somewhat subjective. Plants vary over time and space, so their names are not as fundamental as, for example, the names of chemical elements.
Periodically, a plant is found that looks nothing like any existing type specimen, matching none of their published descriptions. A botanist will then invent a new name for this plant and define a new type specimen. Over the last few decades, about 2500
new plant names were invented per year globally (Prance, 2001) – that is, almost one per year for every 100 species that have a scientific name already. Even for the US, north of Mexico, 60 flowering plant species were described every year between 1975 and 1994, a rate that shows no sign of slowing down (Hartman and Nelson, 2003). Tropical vegetation is particularly rich in plants with no name:
Plant Identification Page 12
