Checklists are lists of plants, often from diverse families, found in a given area, often a national park or part of a country. They may be annotated, with extra information, but the most basic are composed simply of plant names.
Even a basic list of plants compiled at the start of a field guide project is a check-list. For scientifically accurate field guides, you should aim to make this initial checklist as taxonomically rigorous as possible, referencing literature where names were published and listing specimen numbers for your area, unless you are following a Flora with this information in already.
The sorts of additional information that are commonly included in annotated checklists, and highly recommended, are: taxonomic details and references, e.g. place of publication; specimen numbers examined; ecological and geographical range; and basic features of the plant (e.g., ‘5 m tree’). If the list includes many descriptive details of the morphology of the plant, and especially if there are keys to help identify the species, then it is becoming a Flora (the term ‘Florula’ is sometimes used for publications with Flora-like detail, but covering a small part of one country).
Many check-lists were produced over the last century (e.g. Hora & Greenway, 1940) which supported the subsequent development of regional Floras and field guides. Recent global or continental checklists are still extremely useful for creators of field guides: for instance Legumes of Africa (Lock 1989); World checklist of Euphorbiaceae (Govaerts et al., 2000.). The preparation of the Field Guide to the Woody Plants of Western Africa (Hawthorne & Jongkind 2004) was greatly facilitated by the recent completion of Lebrun & Stalk’s (1991-1997) checklists of African plants (data now available online): even without distribution details, the literature references alone, especially for synonyms which are not otherwise available in any database, saved many months work.
Check-lists and your field guide
If your field guide covers more than a few plant species, you should always aim first to make a check-list for your area. Obviously there is a grey area between a complicated annotated check-list and a field guide or a Flora. For planning purposes, you only need to aim for a basic check-list, but you might find it useful to annotate it with extra detail. Basic taxonomic nomenclature should be included (species, authors, and information like place of publication and synonyms, again unless this information is already available in a modern Flora).
Common, less essential but very useful annotations to include in a check-list include:
Common names (dialect, language etc)
Habit (tree, shrub etc.),
Other basic descriptive features (leaves simple/compound, serrated)
Ecology (especially if the area has diverse habitats)
Geography and distribution inside and outside the check-list area.
Other items might, depending on your interests, include details or codes related to usage, conservation, local rarity and so on.
For incomplete-set guides, the check-list should highlight both the species to be included in the guide, and those that might be confused with them. In other words, a check-list should always form as complete a set as possible, even if a field guide based on it does not.
Your check-list will be refined as you work your way towards the final field guide, because you may discover new species as you conduct field work, or new literature. To allow reasonably accurate planning, it is important to make a provisional check-list before planning anything precise, like budgets, time, numbers of pages and so on. There are various ways of going about this.
Unless the field guide is to very well-known species, is very simple and small, or can be based on the contents of a recent flora (where specimens are already listed), you should base a check-list on herbarium specimens of the plants. To do this you will benefit by using a database. BRAHMS is an ideal database system for such tasks.
By using a database, you can integrate your field data collection, check-list production, and species data collection. Hopefully, you can catalogue your images at the same time. As you collect new specimens and document them, you will be able to update a draft check-list automatically.
Obviously, if in weeks of collecting throughout your whole check-list area you discover no new species for your list, then it is at least approaching completion. You can estimate how complete your check-list is for your area by calculating species-area, species-collection or species-time curves. See how many new species have arisen per unit of effort, and if it shows any sign of levelling off.
Publish a check-list before a field guide?
Why not aim to produce a complete checklist as an early publishable landmark of your field guide project? If you are to make a check-list for a little-known area, your check-list might be worthy of publication on its own, for instance in a scientific journal. Maybe you should first target such a publication before returning to plan your field guide? You might then be able to leave some taxonomic ‘baggage’ out of your final field guide. An early, published check-list may also draw constructive criticism about nomenclature from other botanists before the later stages of guide production.
Agencies (like ministries and NGOs) seeking to promote field guides should not shy away from subsidising annotated checklists for large areas if such a list is not available already, however non-user friendly or non-poverty-alleviating they might appear on their own. They will have the long-term effect of facilitating field guide production.