3.2 Plants

Characteristics of plants

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* Are large, multicellular, eukaryotic organisms
* Perform photosynthesis
* Cell walls are composed of cellulose
* Are sessile

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BRYOPHYTES

* Have a protective cuticle and stomata for gas exchange
* Do NOT have vascular tissue or true leaves, roots, or seeds.
* Are generally small because they do not contain vascular tissue
* Needs an environment that is occasionally wet

Example: Sphagnum moss

LYCOPHYTES & PTEROPHYTES

* Have vascular tissues composed of lignin
* Lignin builds strength in cell walls which allows the plant to grow to greater heights.
* Are seedless
* Have large leaves
* Have simple roots and stems

Example: horsetails and ferns

Ligin

Type of organic polymer found in the cell walls of plants that provides structural support and rigidity.

GYMNOSPERMS: The Conifers

* Seed plant
* Reproduce with specialized cones that produce pollen grains and ovules
* Most have needle or scale-like leaves
* Narrow leaves with thick cuticles help with water retention

Examples: pine, spruce and cedar

ANGIOSPERMS: The Flowering Plants

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* Produce seeds within a specialized structure called a fruit.
* Reproduce using flowers