From Seed to Seed:
Plant Science for K-8 Educators
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From Seed to Seed: |
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Gymnosperms.
Conifers are the most common and widespread type of gymnosperm. Gymnosperm
literally means "naked seed" and alludes to the fact that the plants' seeds
are borne exposed. (The angiosperms, on the other hand, bear their seeds
within a protective structure, the ovary.) In the conifers, these seeds
are borne in cones.
Conifers include the familiar pine, spruce, fir, cedar, juniper, and
cypress, as well as the largest living things on earth-the giant sequoia.
Members of this gro Conifers and other gymnosperms such as cycad and ginkgo represent an
evolutionary step up from the ferns, and not only because they protect
their developing embryos in seeds. Unlike the seedless plants, gymnosperms
don't require water to transport sperm to egg, which allows them to freely
colonize dry environments. In addition, these plants possess a vascular
cambium, which allows them to form secondary xylem, or wood. Therefore,
gymnosperms can grow much larger than the more primitive plants which,
lacking a vascular cambium, remain herbaceous. |
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are favored by gardeners for their rich foliage and bark colors and interesting
textures, and because many species are evergreen. In addition, conifers
are the source of much of our lumber and paper products.
