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Gymnosperms
Jessica Harwood
Douglas Wilkin, Ph.D.
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AUTHORS
Jessica Harwood
Douglas Wilkin, Ph.D.
EDITOR
Douglas Wilkin, Ph.D.
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Printed: February 24, 2015
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Niamh Gray-Wilson
Jean Brainard, Ph.D.
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Jane Willan
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C HAPTER
Chapter 1. Gymnosperms
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Gymnosperms
• Define gymnosperm.
• List the four phyla of gymnosperms.
• Give examples of gymnosperms.
What does "gymnasium" mean?
Today a gymnasium means a place for playing indoor sports. In ancient Greece, sports were done in the nude, so the
word "gymnasium" is based on the Greek word for naked (gymnos). The root word is the same for "gymnosperm,"
which means "naked seed." Gymnosperms are those plants that do not have a fruit encasing the seed.
Gymnosperms
Gymnosperms have seeds, but they do not produce fruit. Instead, the seeds of gymnosperms are usually found in
cones.
There are four phyla of gymnosperms:
1. Conifers
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2. Cycads
3. Ginkgoes
4. Gnetophytes
Conifers
Conifers, members of the phylum Coniferophyta, are probably the gymnosperms that are most familiar to you.
Conifers include trees such as pines, firs, spruces, cedars, and the coastal redwood trees in California, which are the
tallest living vascular plants.
Conifers have their reproductive structures in cones, but they are not the only plants to have that trait ( Figure 1.1).
Conifer pollen cones are usually very small, while the seed cones are larger. Pollen contains gametophytes that
produce the male gamete of seed plants. The pollen, which is a powder-like substance, is carried by the wind to
fertilize the seed cones that contain the female gamete ( Figure 1.2).
FIGURE 1.1
A red pine, which bears seeds in cones,
is an example of a conifer.
Conifers have many uses. They are important sources of lumber and are also used to make paper. Resins, the sticky
substance you might see oozing out of a wound on a pine tree, are collected from conifers to make a variety of
products, such as the solvent turpentine and the rosin used by musicians and baseball players. The sticky rosin
improves the pitcher’s hold on the ball or increases the friction between the bow and the strings to help create music
from a violin or other stringed instrument.
Cycads
Cycads, in the phylum Cycadophyta, are also gymnosperms. They have large, finely-divided leaves and grow as
short shrubs and trees in tropical regions. Like conifers, they produce cones, but the seed cones and pollen cones
are always on separate plants ( Figure 1.3). One type of cycad, the Sago Palm, is a popular landscape plant. During
the Age of the Dinosaurs (about 65 to 200 million years ago), cycads were the dominant plants. So you can imagine
dinosaurs grazing on cycad seeds and roaming through cycad forests.
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Chapter 1. Gymnosperms
FIGURE 1.2
The end of a pine tree branch bears the
male cones that produce the pollen.
FIGURE 1.3
Cycads bear their pollen and seeds in
cones on separate plants.
Ginkgoes
Ginkgoes, in the phylum Ginkgophyta, are unique because they are the only species left in the phylum. Many other
species in the fossil record have gone extinct ( Figure 1.4). The ginkgo tree is sometimes called a "living fossil"
because it is the last species from its phylum.
One reason the ginkgo tree may have survived is because it was often grown around Buddhist temples, especially in
China. The ginkgo tree is also a popular landscape tree today in American cities because it can live in polluted areas
better than most plants.
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Ginkgoes, like cycads, has separate female and male plants. The male trees are usually preferred for landscaping
because the seeds produced by the female plants smell terrible when they ripen.
FIGURE 1.4
Ginkgo trees are gymnosperms with
broad leaves.
Gnetophytes
Gnetophytes, in the phylum Gnetophyta, are a very small and unusual group of plants. Ephedra is an important
member of this group, since this desert shrub produces the ephedrine used to treat asthma and other conditions.
Welwitschia produces extremely long leaves and is found in the deserts of southwestern Africa ( Figure 1.5). Overall,
there are about 70 different species in this diverse phylum.
FIGURE 1.5
One type of gnetophyte is Welwitschia.
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Chapter 1. Gymnosperms
Summary
• Gymnosperms have seeds, but they do not produce fruit; the seeds of gymnosperms are usually found in cones.
• There are four phyla of gymnosperms: conifers, cycads, ginkgoes, and gnetophytes.
Explore More
Use the resource below to answer the questions that follow.
• Gymnosperms at http://www.youtube.com/watch?v=zKnrlUI85ys (4:31)
MEDIA
Click image to the left or use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/57445
1.
2.
3.
4.
5.
Which division of gymnosperm has the most living species? How many species are in this division?
Where are cycads most abundant?
Where are conifers most abundant?
What are the characteristics of conifers?
What climate change led to conifers becoming more abundant than ferns? When did this occur?
Review
1.
2.
3.
4.
5.
What features define the gymnosperms?
What are two examples of conifers?
Where are the reproductive structures of conifers located?
What was the dominant plant during the Age of Dinosaurs?
What gymnosperm is known as a living fossil? Explain your answer.
References
1. Keith Kanoti/Maine Forest Service. A red pine, which bears seeds in cones, is an example of a conifer . CC
BY 3.0
2. John Haslam. The end of a pine tree branch bears the male cones that produce the pollen . CC BY 2.0
3. Glenn Fleishman. Cycads bear their pollen and seeds in cones on separate plants . CC BY 2.0
4. Roberto Verzo. Ginkgo trees are gymnosperms with broad leaves . CC BY 2.0
5. Derek Keats. One type of gnetophyte is ”Welwitschia’’ . CC BY 2.0
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