Monocot and dicot (more accurately, many monocots and eudicots) roots share the same basic tissue systems—epidermis, cortex, endodermis, pericycle and vascular tissue—but their internal vascular arrangement differs.
The classic textbook comparison is easiest to see in a cross-section of a young primary root.
At a glance
| Point | Monocot root | Dicot root |
|---|---|---|
| Xylem arrangement | Many xylem poles, often polyarch | Central star-like xylem with fewer arms |
| Pith | Large and distinct | Small or absent in many textbook examples |
| Cambium development | Usually lacks a continuous vascular cambium for typical secondary thickening | Cambium can develop between xylem and phloem in roots capable of secondary growth |
| Secondary growth | Generally absent in typical monocot roots | Common in many woody/herbaceous dicot roots |
| Phloem | Alternates with numerous xylem strands | Located between xylem arms |
| Examples | Maize, grasses | Bean, sunflower and many woody eudicots |
Monocot root
Usually has numerous xylem poles arranged around a prominent central pith, with phloem alternating between xylem strands.
Dicot root
Typically has a smaller number of xylem arms forming a central star or cross, with phloem between them and little/no central pith.
Shared structures
Both root types commonly have root hairs on the epidermal region, a broad cortex, an endodermis controlling movement into the vascular cylinder and a pericycle just inside the endodermis. Lateral roots arise from the pericycle.
So the differences are mainly in vascular pattern and later secondary development, not in the existence of basic root tissue layers.
Secondary growth
In many dicot/eudicot roots, vascular cambium develops and produces secondary xylem inward and secondary phloem outward. This contributes to thickening as the plant matures.
Typical monocot roots do not undergo the same conventional vascular-cambium secondary growth, although some monocots show unusual secondary thickening mechanisms.
Textbook simplification
“Dicot” is a traditional teaching term; modern plant classification recognizes eudicots and several other angiosperm lineages. Anatomy also varies among species.
For an exam, use the standard diagram your curriculum expects, but remember that real plants show exceptions.
Frequently asked questions
Do both roots have endodermis?
Yes, in typical primary anatomy.
Which root has a large pith?
The classic monocot root has a large central pith.
Which commonly shows secondary growth?
Many dicot/eudicot roots do; typical monocot roots do not.
Are all dicot roots identical?
No. The classic star-shaped xylem diagram is a useful generalization, not a rule without exceptions.
KnowDifferences Editorial Team
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