PlantKingdom213-page9 - The eustele, found in most seed...

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Introduction to the Plant Kingdom - 9 Review of Evolutionary Features used in Classifying Vascular Plants Vascular Patterns in Stem and Leaf Stems progress in evolution from a protostele to the siphonostele and eustele vascular patterns. The protostele is a solid core of stem vascular tissue from which leaves diverge without leaving a vascular gap in the stem. The siphonostele has a central pith surrounded by a cylinder of vascular tissue. The vascular strands that go to leaves (the leaf traces) In some plants that have siphonosteles result in a leaf gap of parenchyma cells.
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Unformatted text preview: The eustele, found in most seed plants, is comprised of discrete vascular bundles surrounding the pith. Leaf trace gaps are found in the eustele. Microphylls vs. Megaphylls for leaves Microphylls contain one vascular strand, probably evolving from small projections, or enations located along stem tissue. Megaphylls have a branching system of veins, and probably evolved from side branches of stems, in a webbing process, in which tissue containing chlorophyll filled in spaces between nearby branches. Microphylls Megaphylls...
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