22-5 Angiosperms - Flowering Plants

§    The vast majority of living plant species today reproduce with flowers.

Flowers and Fruits

§    The reproductive organs in angiosperms are flowers

§    Pollination is more efficient than gymnosperms because the flowers attract bees, moths or hummingbirds to transport pollen from flower to flower.

§    Flowers contain ovaries, which surround and protect the seeds.

§    Angiosperm means "enclosed seed"

§    After pollination, the ovary develops into a fruit, which protects the seed and aids in its dispersal.

§    A fruit is a thick wall of tissue surrounding the seed.

§    With animals eating the fruit and then traveling, the seeds can be spread over a wide area.

Diversity of Angiosperms

§    There are many different ways to categorize angiosperms:

v    Monocots and dicots

v    Woody and herbaceous plants

v    Annuals, biennials and perennials

• Sometimes the categories can overlap

v    An iris is a monocot, herbaceous, perennial plant.

Monocots and Dicots

§    The two classes within angiosperms are:

v    Monocots

v    Dicots

§    They are named for the number of cotyledons or seed leaves in the plant embryo.

§    Monocots have one seed leaf, and dicots have two.

§    Monocots include corn, wheat, lilies, orchids and palms.

§    Dicots include roses, clover, tomatoes, oaks, and daisies.

Woody and Herbaceous Plants

§    They are subdivided into groups according to their stems.

§    Woody plants are made of thick cell walls that support the plant body.

►        Trees, shrubs, and vines (grapes and ivy)

§    Herbaceous plants have smooth, nonwoody stems.

►        Dandelions, zinnias, petunias, and sunflowers

Annuals, Biennials and Perennials

§    There are three categories of plant life spans:

v    Annual

v    Biennial

v    Perennial

§    Annuals complete a life cycle within one growing season.

§    They grow from seed to maturity, flower, produce seeds and die all in the course of a year.

§    They include many garden plants: marigolds, petunias, pansies, wheat, cucumbers

§    Biennials complete their life cycle in two years.

§    In the first year, they germinate, grow roots, very short stems and sometimes leaves.

§    In the second year, they grow new stems, leaves, produce flowers and seeds, and die.

§    They include: parsley, celery, foxglove

§    Perennials live for more than two years.

§    Some have herbaceous stems that die each winter and are replaced in the spring

§    Examples: peonies, asparagus, grasses

§    Some have woody stems and they include palm trees, sagebrush, maple trees, and honeysuckle