I. Gymnosperms.

    A. Representatives.
        1. Pines and redwoods.
        2. Cypress.
        3. Ginkgo.

    B. Characteristics.
        1. Most conifers.
        2. Most trees.
        3. "Naked Seed" - no surrounding ovary.

    C. Cycadophyta.
        1. Almost 100 species.
        2. Native only to tropics and subtropical areas.
        3. Resemble palms.
        4. Dioecious - male and female parts on different plants.
        5. Seeds can take 10 years to mature.

    D. Ginkophyta.
        1. Only 1 remaining species: Ginkgo biloba.
        2. Deciduous.
        3. Dioecious.

    E. Gnetophyta.
        1. About 70 species.
        2. Genus Gnetum - tropical vines and trees with large, leathery leaves.
        3. Genus Ephedra - densely branched shrubs that live in arid regions.
        4. Genus Welwitschia - species mirabilis grows in the Namib desert.

    F. Coniferophyta.
        1. 500 - 600 species.
        2. Vital in paper and construction industries.
        3. Monoecious - male and female parts on same plant.
        4. Almost 2 years between pollination and mature seed.

II. Plant structure, general terms.

    A. Epidermis - single-cell thick exterior barrier.
    B. Cortex - thick layer of large, thin-walled cells; often store materials.
    C. Phloem - living transport cells.
    D. Vascular cambium - produces phloem and xylem.
    E. Xylem - dead transport cells.
    F. Meristem - region where cells divide, thus causing plant growth.
        1. Apical meristem.
        2. Vascular cambium.
        3. Cork cambium
        4. Pericycle.
        5. Axillary meristem.
    G. Monocotyledons - 1 cotyledon.
    H. Dicotyledons - 2 cotyledons.

III. Roots

    A. Function: anchor the plant and absorb nutrients.

    B. Types: fibrous and taproot.

    C. Root growth.
        1. Root cap - dead, protective cells.
        2. Apical meristem - dividing cells, lengthen root.
        3. Zone of elongation - new cells growing and differentiating.
        4. Zone of maturation - cells complete their differentiation and cease growing.

    D. Cross section.
        1. Epidermis.
        2. Root hairs.
            a. Protrusion of an epidermal cell to increase surface area of root.
            b. One each per cell.
            c. 100x increase in surface area of root tip.
        3. Cortex.
        4. Endodermis - single-cell thick interior barrier.
        5. Stele (vascular cylinder) - consists of #6-9.
        6. Pericycle - ring of cells that produces lateral roots.
        7. Phloem.
        8. Vascular cambium.
        9. Xylem.

IV. Stems.

    A. Function: support the plant and transport nutrients.

    B. Branching patterns.

        1. Excurrent.
            a. Apical dominance.
            b. Pine tree.
        2. Deliquescent.
            a. Active lateral buds.
            b. Oak tree.
        3. Columnar
            a. Crown of leaves atop an unbranched stem.
            b. Palm tree.

    C. Stem growth
        1. Apical meristem.
        2. Node - location of a leaf.
        3. Internode - stem between leaves.
        4. Axil
            a. The angle formed between the base of the leaf and the stem
            b. Contains a small patch of meristematic cells.
            c. These produce axillary, or lateral buds.

    D. Cross section
        1. Epidermis.
            a. Covered by waxy cuticle.
            b. Has stomata to regulate gas exchange.
        2. Cortex.
        3.  Vascular bundles - consist of phloem on the outside and xylem on the inside, separated by vascular cambium.
        4. Pith - storage tissue; large, thin-walled cells.
        5. Monocots.
            a. Ground parenchyma cells replace the cortex and pith.
            b. Vascular bundles scattered throughout ground parenchyma.
        6. Dicots - vascular bundles arranged in a ring between cortex and pith.
        7. Woody plants.
            a. Epidermis is replaced by cork.
            b. Cork cambium produces more cork as the plant grows.

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