Equi-9

The Embryo has a Root but it is ephemeral & does not form the root system of the mature plant.
Most Roots are formed at Nodes and are therefore called Adventitious.
The underground Rhizome normally produces roots. Aerial Stems do not produce roots unless they become detached or come into contact with the soil.
The Root Apex contains an Apical Cell which produces a Root Cap and the Root Body.

Root Anatomy is one constant in Evolution.

There is an Epidermis, Cortex and Stele.
The Endodermis is the source of Lateral Roots. Consequently, root branching is lateral. This is the same type of branching seen in seed plants and it is regarded as an advanced trait.

Members of the Lycophyta and Pterophyta have Dichotomous Branching & this is regarded as an Ancestral or Primitive trait.
Chalk up another important adaptation for the Endodermis!!!
The Stele is an Actinostele. The Xylem arms appear to radiate from the central xylem mass, like spokes from an axle. The Phloem is located in the depressions between the Xylem arms.

This type of stele is present in the vast majority of plant Roots.

Cross-section of a large Equisetum Root: Note the three regions of the root. The Epidermis is not labeled above but is indicated below.

Stele in a Large Equisetum Root:
It is hard to find good slides of Equisetum roots. The root above is comparatively large. Most Commercial Slides have minute, indistinct root sections.