Division: Tracheophyta

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Division Tracheophyta Vascular Plants
Vascular Plants
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Fern life cycle
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Reduction in Size of the Gametophyte
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The ferns (Phylum Pterophyta) are the largest
group of seedless vascular plants.
They range in size from small, single-leafed
plants to large trees. They are restricted to
at least seasonally moist habitats, since
reproduction relies on motile sperm swimming to
an egg for fertilization. The ferns have leaves
called fronds. Young fronds are curled into
fiddleheads and unfurl as they grow.
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A frond is a mature fern leaf, and these are
often compound (divided into leaflets). A
fiddlehead is a developing baby fern leaf. New
fern leaves are coiled and uncoil as they grow,
thus initially resemble the top of a violin above
the pegs.
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The sporophyte is the dominant part of the life
cycles of vascular plants including ferns. The
spore producing structures, called Sori, are
located on the under-surface of the sporophyte
fronds. Each Sorus is comprised of a cluster
of Sporangia.
Fern frond, a leaf specialized for spore
production
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Sporangium (2n)
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In the ferns, the spores are produced by the
sporophyte in structures called sori (singular
sorus). Spores are often carried long distances
by the wind. A spore germinates and grows into
the gametophyte, which is called a prothallus.
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The Fern Gametophyte
Prothallus
is small inconspicuous.
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The prothallus bears both male and female
gamete-producing structures, the antheridia and
archegonia respectively. Sperm must swim to the
eggs to fertilize them and produce a zygote.
From the zygote a young sporophyte develops
which is attached to the gametophyte
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Fern Gametophyte Prothallus
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There are other groups of seedless vascular
plants with life cycles similar to that of ferns.
All of these groups have flagellated sperm that
require water in order to reach the egg for
fertilization.
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Sporophyte Stage fiddleheads
Gametophyte Stage prothallus
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Whisk fern, Psilotum nudum the simplest vascular
plant alive today. Is a widespread, rootless,
green-stemmed epiphyte. Said to have no leaves
- the aboveground portion of the plant is
regularly branched, with scale-like outgrowths
that resemble small leaves.
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Division Lycophyta Club Mosses
The club mosses are common forest floor plants in
moist temperate woodlands. Many species are
tropical plants that grow on trees as epiphytes.
Tightly packed scale-like leaves cover the
branches and stem. Spores are produced by
sporangia that may be arranged in club-shaped
structures called strobili.
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LYCOPHYTES
Club Mosses
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LYCOPHYTES
Club Moss
Ground Pine
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Division Lycophyta Club mosses
rhizome, an underground, horizontal STEM from
which the roots and branches arise
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Division Sphenophyta horsetails
Only 15 species of horsetails exist today, all in
the genus Equisetum, but they are common in waste
areas and wet places. The name horsetail comes
from the stem with its many whorled branches
covered with small leaves stems are
hollow. Many horsetails have the spore-producing
sporangia arranged in a strobilus on the top of
the stem. Other species have a special stem
that bears the strobilus.
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Division Sphenophyta Horsetails
The epidermal cells of this (and many other)
species of Equisetum contain silica, thus have
been used as pot-scrubbers, earning the plant the
common name of scouring rushes
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See if you can identify the seedless vascular
plants pictured in the next two slides. ?
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Horsetails
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Club Moss
Horsetail
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Review Nonvascular and Vascular Seedless Plants

• A vascular system allows
• club mosses and ferns to
• grow higher off the ground.
• Both groups need free-standing
• water for reproduction.

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Ground Pine
Whisk Fern
Horsetails
Fern
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http//www.hbwbiology.net/quizzes/ch29-early-plant
s.htm Online Quiz Bryophytes and Ferns
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Mosses
Ferns
Compare /Contrast Mosses Ferns