XVI International Botanical Congess

Since online identification programs first appeared about 30 years ago a large number of such programs have been published. No attempt will be made to review all these, but the features that are needed in such programs will be discussed and justified. In many ways, such programs resemble expert systems. It is most important for these programs to use a standard data definition and the necessary features of this will be discussed. Interactive but otherwise conventional keys are also published and these will be contrasted with online programs.