Plants B 3.3 Seed Plants

Seed Plants The seed plants generally are classified into two major groups—gymnosperms (JIHM nuh spurmz) and angiosperms (AN jee uh spurmz). The seed plants generally are classified into two major groups—gymnosperms (JIHM nuh spurmz) and angiosperms (AN jee uh spurmz). Leaves are the organs of the plant where the food-making process—photosynthesis— usually occurs. Leaves are the organs of the plant where the food-making process—photosynthesis— usually occurs. Most leaves have small openings in the epidermis called stomata (STOH muh tuh). Most leaves have small openings in the epidermis called stomata (STOH muh tuh).

Stomata

Seed Plants Each stoma is surrounded by two guard cells that open and close it. Each stoma is surrounded by two guard cells that open and close it. Materials move between leaves and roots through the vascular tissue in the stem. Materials move between leaves and roots through the vascular tissue in the stem. Plant stems are either herbaceous (hur BAY shuns) or woody. Plant stems are either herbaceous (hur BAY shuns) or woody.

Seed Plants Water and other substances enter a plant through its roots. Water and other substances enter a plant through its roots. Roots can store food. When you eat carrots or beets, you eat roots that contain stored food. Roots can store food. When you eat carrots or beets, you eat roots that contain stored food. Xylem (ZI lum) tissue is made up of hollow, tubular cells that are stacked one on top of the other to form a structure called a vessel. Xylem (ZI lum) tissue is made up of hollow, tubular cells that are stacked one on top of the other to form a structure called a vessel. Phloem (FLOH em) is a plant tissue also made up of tubular cells that are stacked to form structures called tubes. Phloem help move food. Phloem (FLOH em) is a plant tissue also made up of tubular cells that are stacked to form structures called tubes. Phloem help move food.

Seed Plants Cambium (KAM bee um) is a tissue that produces most of the new xylem and phloem cells. Cambium (KAM bee um) is a tissue that produces most of the new xylem and phloem cells. Gymnosperms are vascular plants that produce seeds that are not protected by fruit Gymnosperms are vascular plants that produce seeds that are not protected by fruit Four divisions of plants—conifers, cycads, ginkgoes, and gnetophytes (NE tuh fites)—are classified as gymnosperms. Four divisions of plants—conifers, cycads, ginkgoes, and gnetophytes (NE tuh fites)—are classified as gymnosperms. All conifers produce two types of cones—male and female. All conifers produce two types of cones—male and female.

Male Cone Female Cone

Seed Plants An angiosperm is a vascular plant that flowers and produces fruits with one or more seeds. An angiosperm is a vascular plant that flowers and produces fruits with one or more seeds. A cotyledon is part of a seed often used for food storage. A cotyledon is part of a seed often used for food storage. Monocots have one cotyledon inside their seeds and dicots have two. Monocots have one cotyledon inside their seeds and dicots have two.

Seed Plants If a plant's life cycle is completed within one year, it is called an annual. If a plant's life cycle is completed within one year, it is called an annual. Plants called biennials (bi Eh nee ulz) complete their life cycles within two years. Plants called biennials (bi Eh nee ulz) complete their life cycles within two years. Angiosperms that take more than two years to grow to maturity are called perennials. Angiosperms that take more than two years to grow to maturity are called perennials.

Annuals Perennials

Seed Plants  Angiosperm  Gymnosperm  Xylem  Phloem  Cambium  Cotyledon  Annuals and perennials