Section 4: Flowering Plants
Flowers come in a variety of colors, shapes, and sizes. However, they all have one function, which is reproduction. Each flower contains four specialized organs: the sepal, the petal, the stamen, and the pistil. The sepal is the leaf-like structure that covers and protects the flower bud before it opens. The petal is the most colorful part of the flower. It helps guide and attract pollinators, like birds and insects, towards its center. Pollen grains then transfer to the insect, who will take the pollen to the next flowers they visit. The stamen is the male reproductive organ. It consists of a stalk, called a filament, on which the anther sits on top. This is where pollen is produced. The pistil is the female reproductive organ. On top of the pistil is a sticky top called a stigma. The stigma is connected to the ovary by a slender tube called the style. The ovary is where ovules grow into a seed if fertilized.
Angiosperms are divided into two groups called monocots and dicots each with distinct characteristics and features. Palm trees, bamboo, and all types of grasses are monocots. Monocots have seeds with one cotyledon and leaves that have parallel veins. Their vascular tissue is organized into bundles in a scattered pattern. Their flowers have petals arranged in multiples of three and they also have fibrous root systems. Most flowering plants are dicots. They have seeds with two cotyledons, branched veins on their leaves and vascular bundles arranged in a ring. Their floral parts are in multiples of four or five, and they have taproots, which allow plants to grow tall.