The field of genetics began with the study of plants. Recent genetic analyses using the model plant, Arabidopsis, have elucidated pathways regulating many facets of plant development. Mutations have been identified that affect embryonic, shoot, root, and floral development. Common themes emerging from the characterization of the affected genes have been the importance of transcriptional regulation and intercellular signaling as well as a central role for the plant growth regulator, auxin.