How many ways are there to make a root?

Plants often make the same organ in different development contexts. Roots are a quintessential example, with embryonic, primary, lateral, adventitious, and regenerative roots common to many plants. The cellular origins and early morphologies of different roots can vary greatly, but the adult structures can be remarkably similar. Recent studies have highlighted the diversity of mechanisms that can initiate roots while late patterning mechanisms are frequently shared. In the middle stages when patterning emerges, evidence shows that antagonistic auxin–cytokinin interactions regulate tissue patterns in root embryogenesis, vascular organization, and regeneration but it is not yet clear if a common ontogeny for the root body plan exists.