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7 Cards in this Set
- Front
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Seed Plants
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a) have pollen, carried by wind or animals, instead of sperm.
b) do not have a separate gametophyte plant, instead the female gametophyte is protected inside the seed. c) seeds are much larger than spores, with big food reserves so they can live much longer before germinating. >All are heterosporous ( pollen and egg cell ). They first evolved about 400 million years ago. |
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Gymnosperms
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>Gymnosperms have naked seeds (not surrounded by the ovary). They are the earliest seed plants
that evolved. >They do not have any flowers, instead the seeds are produced in cones. >Gymnosperms (such as pine trees) are usually wind pollinated. >Present day gymnosperms are divided into four phyla: Gnetophyta, Cycadophyta, Ginkgophyta, Coniferophyta |
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Gnetophyta
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>Close relatives of flowering plants ( angiosperms ). >Two main genera survive today : Ephedra and
Welwitschia. |
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Ephedra
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Ephedra is a desert plant ( western US ) with tiny leaves. It produces nectar to attract insects for
pollination. Common name: "Mormon tea", it is used medicinally by native Americans. Ephedra contains ephedrine, used to treat asthma, hay fever. Dietary supplements containing Ephedra were banned in 2004, after they were linked to over 100 deaths. Pseudoephedrine is used in cold medication (also used in making methamphetamine). |
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Welwitschia
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Welwitschia is a desert plant ( Africa ) with only two leaves, and a long tap root. It gets most of its
water from fog and dew that condense on the leaves at night. Fossils of Welwitschia are almost 300 million years old. |
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Cycadophyta
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>Mainly tropical / subtropical.
>Cycads are often planted ornamentally ( Common name "sago palms" no, they are not related to palm trees, which are flowering plants!). >Cycads are dioecious >Wind pollinated ; pollen tube grows close to the egg, then releases sperm. |
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examples of cycadophyta
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genus Cycas (Sago palm) Sago palm. Commonly planted in Florida, it is native to Asia.
Zamia (Coontie, or Arrowroot) This is native to Florida. The Timucuan tribe of North Florida ground up the roots of this plant to make bread. |
