Identification and access methods
Plant identification is the process of establishing which name to apply to a particular plant or derived specimen. In terms of how we think, and ruling out the ‘ask someone else’ option, there are two rather different modes of identification, whether the name is a scientific one or not:
- Identification through recognition. This is the holistic method, apparently involving the instantaneous appreciation of many parts of the plant at once.
- Identification through analysis. This is a more rule-based method, involving a sequential series of considerations about individual characteristics.
The dilemma between promoting recognition or analytical identification is central to the challenge of writing any plant identification guide. You cannot rely entirely on lists of features that experts recognise. It is the task of a field guide writer to explore and discover rules that enable plants to be distinguished in the field and to know when to rely on pictures alone. There may be no one in the world who consciously ‘knows’ all of the diagnostic rules you need in your field guide - existing botanical works will probably not contain all the answers either - so do not expect to find them entirely by asking experts or reading books.
However, field guides in particular have traditionally made good use of identification through recognition, by including pictures of whole animals, plants or flowers with little diagnostic text or other such help. For bird field guides, the situation is even more extreme, with “birders” strongly favouring browsing. Stevenson et al. (2003) even distinguish “field guides” from “keys”, as if by definition a field guide is always less analytical – a distinction with which we do not agree. Larger animals in general, especially birds, are more amenable to this approach than plants, as there are fewer of them, and visual signals have often been important in their own evolution.
Field guides have two main types of content: the actual descriptive material, often both text and associated pictures which describe the plants; and indexing, arrangement or keying elements – the access methods - to help readers identify or reach plants they are interested in. Our definition of a field guide has identification as a definitive feature, so an access method that enables navigation to the right species based on its details is generally crucial.
Most access methods work with an analytical approach to identification, although browsing – simply leafing through pages and pictures - in a valid access method and this relies largely on recognition; a mixture of browsing and analysis is often a fruitful combination. The descriptive material (including pictures) should at least allow verification of an identification. Simple guides may work well with an access method that involves only browsing of descriptions, and this browsing-only approach may even work for the more dogged enthusiasts with larger reference books. However, there will usually be too many species in a tropical forest guide to make browsing of all descriptions an efficient option, so a specific access method, independent of the descriptions, may well be needed.
When considering the options for access methods, we have to distinguish static and dynamic formats of field guide.
Static formats include virtually all early field guides, notably books, and a majority of current ones. In static formats, the content, sequence and format are fixed at the time of publication. Keys and other types of access method have been developed to help users navigate to the right pages and species.
In dynamic formats, the order and sometimes other aspects of the content of a guide can be rearranged during use, or at least after initial publication, either because it is on a computer or by using mechanical devices like card indexes and ring binders. The access method can be interactive, so it is often possible to allow various optional methods to suit different types of user or different seasons.
There are many factors to weigh when selecting the format appropriate to your needs. Here is a summary of some of the pertinent points.
Computer –based dynamic guides and field use
There is some evidence, but more in the way of untapped potential, that dynamic computer formats will revolutionise field guides by making the access of information more user friendly and more flexible, even if the guide is ultimately to be printed for field use. Sites on the internet or databases on a CD-Rom will increasingly produce guides customisable for species and geographical coverage.
- In interactive keys, users can avoid or delay questions they cannot answer. This is particularly valuable in the field, where only fragments of plants may be available.
- Modern students are generally comfortable with ‘point and click’ browsing approach to information, and such software may draw some to tropical botany if the interface seems trendy and modern, regardless of the content or usability.
- If a decision is bothering you or there is a conflict amongst potential users (which species should I include?; should I emphasise local or Latin names?), maybe you could supply both formats, or species lists, with software ‘switches’ to change between them.
- There is but slow improvement in interactive identification compared to other software, but these guides do increasingly allow reasonable illustration of taxa, with multiple images, maps and textual information, to be viewed when necessary to confirm an identification by selecting the appropriate link. In book format all of this information would soon add up to a key heavier than a computer.
The potential for non-computer dynamic formats of field guide
A printed, (or printable) modular guide project stands to provide a platform whereby funders pay once per species and see them used variously in different environments; independent workers can collaborate to contribute to a wide field guide effort; and users from many backgrounds can take their results and adapt them to their own need. Identification would be based largely on browsing, facilitated by a structure put into place by the consortium, and this would be useful for facilitating the international aspects of such projects.
- Modular guides and other dynamic formats can be updated without a major revision
- Dynamic novel formats often attract more interest amongst students whose botanical interest has yet to be turned on than, say, a static format book, because they are interactive, and are unusual. As novelties, they may be more sellable than standard books.
Static formats: classic formats still the best option for many users
Do not underestimate the value of a basic indented dichotomous key. Whilst they may not always be fashionable, they represent a clear and an efficient way of displaying information for a decision tree.
Try and break up all keys into sections that fit on one page. Some information about a plant will almost certainly have to be observed anyway (e.g. leaves simple or compound; tree/climber etc.), so there is no harm in steering all users through these questions, and little advantage to allowing users to avoid answering such questions early on in their decision-making process, as is advocated for multi-access keys.
Multi-access keys are convenient tables for summarising much information that might otherwise become hidden in a dichotomous key, but the more comprehensive they are the more complicated they are to use. They are very appropriate for flower, fruit and other seasonal data which may be missing when the plant is observed, but if present make identification simpler.
More information is needed for a complete data matrix for an interactive key than for a static dichotomous key, as all possible routes to an answer have to be planned for. Dynamic keys often involve more work and non-botanical skills to produce than static guides. This extra investment may be at the expense of a solid, yet still workable, standard static guide approach.
There is a danger that machine customised field guides will look somewhat uncreative and ‘mass-produced’, like internet catalogues, and therefore not capture the imagination of users. Designers of static guides can more explicitly steer the users around difficult questions, tweak the format to suit the species and users, and avoid variable or easily misinterpreted statements without fuss.
Book users need less training than computer users, especially if they are not comfortable with computers. The layout of a book is globally well-understood.
Books at least are mostly more practical for field work in tropical forest than dynamic formats. When computers are involved the hardware may end up being less convenient, portable or affordable than a basic book. Personal Digital Assistants (PDAs) are not yet powerful enough (in 2004), but they are bound to be in a few years.
Identification software and hardware has some years of improvement before the graphics in particular are as good as they could be, or as readable as a good book.
Often the instigators and makers of identification keys are taxonomists who may not have much incentive or skill to produce their work in the form of an interactive key. The more familiar printed medium suits their purpose adequately in the herbarium, earns more academic credit and works during power cuts. Dynamic formats are currently harder to publish for scientific citation. If you are, or are working with a scientist in an institution, their future employment may well depend on production of easily peer-reviewed publication in a static format. This will presumably change as more information is published electronically.
In educational terms, the lack of a rigid structure engendered by dynamic formats might make learning of the plant groups harder.
Computers are not universally available. Workers in institutions with limited resources may not always have access to the computers that exist. Local technical support might be lacking. Books do not need technical support and are ‘future-proof’. Computers consume bench space, and require air-conditioning and a reliable and protected power supply. They are more likely to be hi-jacked for other uses.