The paper describes the experience of project Dryades, coordinated by the University of Trieste, in developing interactive identification keys in the form of applications for mobile devices (iPhone / iPad / iPodtouch). All of our keys were previously generated from a database of morpho-anatomical characters using software FRIDA. The applications for mobile devices, which were tested Europewide during the project KeyToNature, have proved to be useful in education, in the promotion of nature-aware tourism, and in projects of citizen science. The first-generation apps were stand-alone packages which consisted into a sequence of stand-alone HTML pages, while those of the second generation do incorporate the digital key as a true database into the mobile device. All of the hitherto published applications are basically in the form of illustrated dichotomous keys. Future developments will include also a multi-entry query interface, and will be extended to devices which use the Android system.
