The organization of roots of dicotyledonous plants and the positions of control points

The structure of roots has been studied for many years, but despite their importance to the growth and well-being of plants, most researchers tend to ignore them. This is unfortunate, because their simple body plan makes it possible to study complex developmental pathways without the complications sometimes found in the shoot. In this illustrated essay, my objective is to describe the body plan of the root and the root apical meristem (RAM) and point out the control points where differentiation and cell cycle decisions are made. Hopefully this outline will assist plant biologists in identifying the structural context for their observations.