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Dicot stem
Monocot stem
Broad pith
Weak stem
Monocot fiber sheaths
Ordinary cortex
Aerenchyma hypodermis
Aerenchyma cortex
Aerenchyma cortex 2
Stem endodermis
Palisade cortex
Cortical bundle
Capped cortical bundles
Collapsible cortex
Perimedullary fibers
Conjunctive tissue, paren.
Torn pith
Hollow pith
Medullary bundles
Typical dicot bundle
Vascular ring
Typical monocot bundle
Amphivasal bundle
Corn vascular bundle
Clintonia bundles
Protoxylem
Metaxylem
Metaxylem parenchyma
Metaxylem fibers
Internal phloem
Internal phloem, mag
Developing metaxylem
Primary phloem
Phloem fiber cap
Developing fibers

Fig. 11.1-5. Transverse section of rush stem (Juncus). Rushes live in wet areas and their stems grow to be about two to four feet tall – about one meter – supporting themselves. They are monocots, so they do not form wood, and all their strength comes from three primary tissues:

1) the fiber sheaths around each vascular bundle,

2) the cells of the conjunctive tissue also have thick walls, and

3) the strength of the secondary walls of the tracheary elements themselves (the tracheids and the vessel elements).