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Spore-Producing
Vascular Plants
2. Pteridophyta
Ferns
spore-producing
vascular plants
Ferns are sporeproducing vascular
plants that have true
leaves, roots, and
stems. Ferns are often
grown as houseplants.
The parts of a fern
The fern's underground
stem is a rhizome. Fern
rhizomes grow parallel
to the surface of the soil.
Many small roots grow
from the bottom of
rhizome.
Young leaves grow from
the top of a rhizome. A
young, coiled fern leaf is
called a fiddlehead.
As a fiddlehead grows, it
uncoils and develops
into a frond, a mature
fern leaf.
Some formed ancient
forests were tree ferns.
Over millions of years,
these plants were buried
by sand and soil. The
mass of the sand and
soil produced great
pressure and heat.
Eventually the pressure
and heat changed the
ferns and other plants
into coal, oil, and
natural gas.
Fern Life Cycle
The small, brown
spots on the underside
of a fern frond are
spore cases. This is
called a sorus (plural,
sori).
Clusters of
spore
cases, or
sori, on a
licorice
fern.
Figure:The tiny
brown spots on
the underside
of this fern
frond are spore
cases.
The curled
structures at
the tops of
these ferns
are called
fiddleheads.
Into what
structures do
fiddleheads
develop?
Sori are produced
during the asexual
stage of a fern's life
cycle. Spores released
from the sori are
dispersed by wind and
water.
The fern's life cycle has
two stages. One stage is
called the sporophyte
stage and the other is
called the gametophyte
stage. Which stage
produces the male and
female sex cells
If a spore lands in
moist shaded soil, it
can germinate and
grow into a heartshaped plant.
The heart-shaped plant
is the beginning of the
sexual stage of the life
cycle. Tiny sex organs
form on its underside.
Sperm from the male
sex organ swim
through water to the
female sex organ. A
sperm fertilizes an egg,
and the zygote grows
into an embryo.
The embryo, protected
and nourished by the
heart-shaped plant,
develops into a mature
fern. Sori appear on the
mature fern, and the
cycle begins again.
Horsetails
Horsetails are sporeproducing vascular
plants with hollow,
jointed stems and
scalelike leaves,
Some horsetails change
their appearance
between spring and
summer.
Figure: Left: Horsetails in early
spring make and disperse spores
Right: In late spring, bushy green
stems carry on photosynthesis.
Club Mosses
It is a small evergreen
plant that looked like the
plant. This plant has small
mosslike leaves that are
closely arranged on its
stem. On top of the plant is
a club-shaped structure.
For these
reasons,
this plant
is named
a club
moss.
Club mosses are
spore-producing
vascular plants with
branching stems and
tiny, scalelike leaves.
In fact, some club
mosses look so
much like young
pine trees that
people call them
ground pine.
Club Moss.
Living club
mosses are
generally small,
but prehistoric
members of this
group were the
size of trees
Spores are
produced in the
club-shaped spore
cases at the ends of
certain upright
branches.
Like ferns and
horsetails, club mosses
have both an asexual
and sexual stage in
their life cycle. But the
life cycle of a club moss
may take as long as 15
years to complete!
Lesson Review
1. How do tree ferns that
lived in ancient forest
affect your life today?
2. What organs evolved
in ferns that never
evolved in bryophytes?
3. What is the difference
between a fiddlehead and a
frond?
4. Where would you find the
spore case of a horsetail?
A club moss?
Interpret and Apply
6. Why are most sporeproducing vascular plants
larger than most bryophytes?
7. A certain fern stops
producing spores, eggs, and
sperm. Yet, the