Root Directory
| Two = Diarch |
| Three = Triarch |
| Four = Tetrarch |
| Five = Pentarch |
| Six = Hexarch |
| More than five = Polyarch |
Monocots are usually Polyarch. Bundles of Phloem alternate with the Xylem arms. The xylem contains many lignified cells in older portions of the root. The phloem stands out because its cells have thin, unlignified cell walls.
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Cross-section of Clintonia (monocot) Root. Count the number of xylem arms. |
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Cross-section of Smilax (monocot) Root. The tracheary
elements of the Xylem are the cells with the largest diameters. Count the number of xylem
arms. |
Smilax root at higher magnification. Locate the Xylem and Phloem as well as the Endodermis, Cortex and Epidermis. |
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| Smilax Stele showing bundles
of Phloem alternating with Xylem
Vessel Members. The cell pattern is distorted by the extreme enlargement of the Vessel Members. |
Smilax root showing the Stele, Endodermis, Cortex, Exodermis & Epidermis. The Exodermis has the same anatomy as the Endodermis and probably restricts water loss to the outside in older roots. |
