The root ( radicle) extends down into the soil to absorb water and nutrients, the stem ( hypocotyl) grows upward, and the leaves ( plumule) open to capture sunlight and make food for the plant by photosynthesis. In conifers, the seeds are formed inside the cones, which enlarge and protect but don’t fully enclose them. In the in flowering plants, which dominate the world’s vegetation, seeds form and ripen inside the flower’s ovary, which then matures into a container called a fruit. When we think of a fruit, we may imagine the soft, fleshy varieties that satisfy our palates, like apples, melons, or berries. However, many plants produce dry woody or papery fruits. A fruit may enclose just one seed (like a sunflower seed) or many (like a milkweed pod.) If a whole group of fruits grow close together, as in Queen Anne’s lace or goldenrod, we call it a seed head. Nuts like acorns and beechnuts are seeds enclosed in woody fruits. Plants in the legume family, like peas and beans, enclose their seeds in pods, arranged in a single row. Looking at a bean or pea we can see a slight depression, called the hilum, where it was attached to the pod. As the pod dries out, it splits along a seam to release the seeds. Valued as a food source of humans and livestock, other plants in the legume family include alfalfa, peanuts, lentils, clover, and soybeans. Seeds need to move away from the parent plant to avoid competition for sunlight, water, nutrients, and space, and they have many ways to travel. Seeds and their containers use wind, water, animals or mechanical means to reach new locations. Some plants use force to eject their seeds from spring-loaded containers. The capsules of violet, columbine, witch hazel and jewelweed burst open when they mature, propelling the seeds through the air.
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