Cross section of a root: axis of the plant which grows in the opposite direction from the stem, maintain the plant in place and absorbs nutrients.
Piliferous stratum: set of cells on the outer layer that carry the root hairs.
Cortex: part of the root that protects the pith.
Xylem: woody parts of the root.
Phloem: vessels through which sap circulates.
Pith: central part of the root.
Phellogen: part of the root that produces cork.