stele

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EUSTELE Here we see the development of vascular
systems, in which the LEAF dominates the
vascular system.
Vascular bundles are arranged in a RING. May be
COLLATERAL, or BICOLLATERAL.
Stele
Cortex
ATACTOSTELE
Stem contains a ring of vascular bundles, and
then a spiral towards the centre.
This represents the highest level of development
of the vascular system in the stem. Stippling
and hashes left out for clarity.
KEY
XYLEM PHLOEM
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STEMS and ROOTS
Structurally, the same cells are found, but
arranged differently. In addition, little if any
need for structural support in roots. Both
contain cortex in young organs, but not all roots
contain a stele.
The stem Clearly defined CORTEX and STELE
The Root CORTEX, but STELE replaced by
parenchymatous central region -- more stele-like
in MONOCOTYLEDONS than in DICOTYLEDONS