Flowers, Fruits, and Seeds Outline

• Dicots versus Monocots

• Structure of Flowers

• Fruits

 Fleshy

 Dry

• Fruit and Seed Dispersal

• Seeds

 Germination

 Longevity Structure of Flowers

• Each flower, which begins as an embryonic primordium that develops into a bud, occurs as a specialized branch at the tip of a peduncle which may have branchlets of pedicles.

 Pedicle swells at its tip into a small pad (receptacle).

- Other parts of the flower are attached to the receptacle. Structure of Flowers

• Outermost whorl of parts that typically grows from the receptacle is of three to five sepals.

 All together, the whorl or sepals is called the calyx.

• Next whorl consists of three to many petals. All of the petals together are called the corolla.

 The reason you see so many different types of flowers are because of the ways plants modify their corollas to attract different pollinators.

 Calyx and corolla together form the perianth. Structure of Flowers

• After the petals, flowers have a whorl of male parts called stamens.

 Little bags of pollen at the tips of the stamens are called anthers. Anthers contain sporangia. The spores produced there develop into pollen grains containing sperm cells.

 The slender stalks that support the anthers are called filaments. Structure of Flowers

• The most central whorl of parts within a flower consists of female carpels– green, vase-like structures. In many flowers, more than one carpel fuses together to form a compound carpel, also called a pistil. Structure of Flowers

• Each carpel or pistil has three parts:

 The tip of the pistil is the stigma. Pollination occurs when pollen grains land on the stigma.

 The long tubular part of the pistil is called the style. Pollen grains grow long tubes down through the style in order to reach the base of the pistil. Structure of Flowers

• The swollen base of the pistil is the ovary. Inside the ovary are chambers that contain one or more ovules. After the ovules are The ovary (purple) contains fertilized with sperm ovules (green). The ovules from the pollen, they are the female sex cells, and when fertilized they grow will develop into into the seeds of the plant. seeds. Structure of Flowers

• One way that flowers can look different from each other is based on the position of the ovary relative to the calyx and corolla.

 Superior Ovary - Calyx and corolla are attached to the receptacle at the base of the ovary.

 Inferior Ovary - Receptacle grows up and around the ovary.

- Calyx and corolla appear to be attached at the top. Structure of Flowers

Superior Ovary Inferior Ovary Generalized Flower Dicots versus Monocots

• Dicots • Monocots

• Two cotyledons • One cotyledon • Flower parts in fours or • Flower parts in threes fives • Leaves with parallel • Leaves with distinct vein network primary veins. • Vascular cambium • Vascular cambium present absent

• Vascular bundles in • Vascular bundles ring scattered

• Pollen grain with three • Pollen grain with one apertures aperture