Arabidopsis thaliana is an important model for flowering plants. Analysis of the sequence of this genome is giving us access to a considerable quantity of data which will lead to an understanding of plant function, as well as important information about conserved processes in all eucaryotes. In particular, a catalogue of the genes which participate in the life cycle of a plant has been developed. This catalog is probably imperfect, because the genes that it contains are essentially based on predictions, and in the majority of cases, their function is hypothetic at best. Nevertheless, this catalog makes it possible, for the first time, to evaluate the scope of the work that remains to be done in order to comprehend the biological processes in the life of an angiosperm.