Just like conventional dichotomous keys interactive multi-access keys require users to answer questions in order to name taxa. However, in this case the user can choose which questions to answer, and in what order – in other words, the user controls the identification process, rather than the key-builder. This feature provides a solution to, or at least ameliorates, the problem of the ‘unanswerable couplet’ that can adversely affect use of conventional dichotomous keys. Furthermore, with interactive multi-access keys the user can choose to use “easy” characters early-on in the identification. For example, in Acacia quantitative measurements such as phyllode length and width have proven especially powerful in discriminating species of Acacia. Because of their variable nature such characters cannot normally be used early-on in conventional keys. Most multi-access keys also allow users to select more than one answer to multiple-choice questions. This is important, because users are not forced to make a decision between qualitative character-states which, by their nature, may differ only by degrees. There are many other attractive features of interactive multi-access keys. For example:
- the computer programs can scrutinise character lists dynamically to find the best ones to use in order to identify a specimen most quickly (this is particularly useful if the user is not familiar with the group of organisms being keyed);
- suspect or wrong answers can be quickly deleted without having to backtrack laboriously through the key;
- context-sensitive help, perhaps in the form of annotated images or notes, can be provided to help with technical jargon or difficult characters;
- once an organism has been named it is simple to deliver a cluster of information about it, such as drawings, photographs, videos, sounds, distribution maps and notes.
Interactive multi-access keys are especially useful when dealing with large groups of organisms. In fact, in a genus of the enormous size and variability of Acacia, electronic keying is the only way to name specimens reliably and efficiently when dealing with species on a continent-wide basis. The recently published electronic key WATTLE: Acacias of Australia provides interactive identification for the entire Australian Acacia flora. This key greatly empowers the user and makes the identification process reasonably simple. Helpful notes on how to best use the WATTLE key are provided in WorldWideWattle.
Interactive multi-access keys need not be restricted to providing names for taxa. They can also be very effective in selecting taxa that conform with non-morphological criteria such as environmental, biological or utilisation attributes. In this way one can, for example, list all species occurring in a particular geographical region, or those suited to commercial wood production, effective as wind breaks, helpful in salinity control, and so forth. The electronic key to Acacia species of the Kalannie region was constructed with environmental utilisation in mind.
It is inevitable that in the future interactive multi-access keys will become far more common than they are now. These electronic tools are powerful, flexible, easy to use and are efficient at guiding users to correct answers. Perhaps most importantly, they enable an increasingly small pool of taxonomic experts to “clone” their knowledge for wide distribution.