Plant Classification One of the traits used in but there are others.

Quiz 12C
Plant Classification
One of the traits used in
classifying plants is the
presence or absence of
vascular tissue. Xylem and
phloem are the most familiar,
but there are others.
Vascular plants: plants that have
vascular tissue.
Nonvascular plants: plants that do
not have vascular tissue.
Do you think that plants without
vascular tissues are tall or short?
Why?
Another important trait used to
classify plants is whether they
produce seeds.
Nonvascular plants – seedless and
reproduce by producing gametes in one
stage of their life cycle and spores.
Vascular plants – some reproduce by
gametes and spores & others by
gametes and seeds.
The 3 Major categories
of plants
Plant Divisions
Non-vasuclar
Moss
Liverworts
hornworts
Vascular without Seeds
ferns
wiskferns
ground pine
Vascular with Seeds
conifers
monocots
dicots
Non-vascular plants
Phylum Bryophyta
moss
liverwort
hornwort
Non-vascular plants
These plants are called
bryophytes.
Phylum Bryophyta (means
“mosslike plant”)
Non-vascular plants
• Water and other
materials are transported
by diffusion.
• Fairly short.
Non-vascular plants
• Sometimes have parts that look like roots,
stems, or leaves, but there is no vascular
tissue so they don’t have roots, stems, or
leaves.
• Live near water
or shady places.
Just because a plant has the word
“moss” in its name, doesn’t make it
moss. Examples …
 Irish
moss (algae)
 Reindeer moss (lichen – fungus &
algae
 Spanish moss (flowering plant)
Irish Moss
Reindeer Moss
Spanish Moss
Parts of a moss plant
leafy shoot- a slender stalk with leaflike
structures; each of the tiny leaflike
structures on moss is 1 cell layer thick
rhizoids- tiny hairless threads which
grows into the soil to absorb water and
minerals; not roots- lack conditioning
tissue
Parts of a moss plant
Leafy Shoot
Rhizoids
Moss Leafy Shoot
Life Cycle of Moss
Alternation of Generations
•Sporophyte Generation: produces
spores (asexual)
•Gametophyte Generation: produces
gametes (sexual)
Life Cycle of Moss
Gametophyte Generation
1. The top of the male gametophyte bears the
antheridia which produces sperm
2. The top of the female gametophyte has
one or more archegonia which contains the
ova
3. Sperm swim from the antheridia to the
archegonia and fertilizes an ovum (zygote)
Life Cycle of Moss
Sporophyte Generation
4. Zygote grows into a stalk with a capsule which
produces spores
5. When mature the cap comes off and spores disperse
6. Spore grows when environmental conditions are
right
7. First grows into a cellular filament called a
protonema
8. Protonema then forms the leafy shoots and rhizoids
Life Cycle of Moss
Protonema
Moss
Moss Capsule
Liverworts
“Liver Plant”
Marchantia – a
common liverwort with a
y-shaped thallus
Have splash platforms
which look like little
umbrellas
Benefits of Mosses
• Help to replenish the soil
• Help to prevent soil erosion
• Peat moss or Sphagnum is used by
gardeners to pack plants for shipment and
in Iceland and other northern regions it is
used as fuel
• Has been used for surgical dressing
Phylum Pterophyta
Vascular Plants Without Seeds
Ferns
Ferns:





nonflowering vascular plants
Spore-bearing
leaves
Horizontal
undergound stems
1-2 feet tall
Tropical ferns may
grow as tall as 60 ft.
with fronds 12-14
ft.
Some are epiphytes
Parts of a fern:



Fronds – leaves
Rhizome – a
creeping or
underground stem,
which produce roots
Sori – groups of
spore-bearing
sporangia (means “a
heap”)
Fern Sori
Sori may
be round,
kidneyshaped,
oblong,
linear,
curved, or
starshaped.
Sporophyte Generation of Ferns
A new fern’s life cycle
typically begins in July
with the appearance of
sori on the
undersurface or along
the margins of a frond.
Sporophyte Generation


Sori appear on
the underside of a
frond.
Sori first open
and discharge
millions of
spores.
Gametophyte Generation
Spore develops into
a tiny green, heartshaped structure
called a prothallus.
Seldom seen, only 1
cell layer in thickness.
Gametophyte Generation
The underside of the prothallus develops
archegonia and antheridia
Antheridia near
the point (sperm)
Archegonia at notched
end (ova)
Gametophyte Generation
Sperm are
released from
the antheridia
and swim to the
ovum at the
bottom of the
archegonia.
Sporophyte Generation
Zygote matures and sends
the first leaf up and the first
root down.
The first leaf is often a fanshaped blade.
The second leaf is usually a
fiddlehead, a coiled young
leaf. Some fiddleheads are
edible and used in salads.
Fern Alternation of Generation Facts
Ferns usually require
3-7 years to reach
reproductive maturity.
Dominant generation:
Sporophyte
Fern plants
(sporophytes) live for
several years and
produce new fronds
each year
Fern Alternation of Generation Facts
Protellia
(gametophytes) only
live 3-7 weeks, in
which time they
produce the archegonia
and antheridia.
Dominant generation:
Sporophyte
Other seedless vascular plants:
club moss, whiskfern & horsetail
club moss
whiskfern
horsetail
club moss
club mosses: (also
called "ground pine"
because they grow
along the ground in
temperate regions)
horsetail
• all but one group have
become extinct
• the epidermis contains a
glasslike substance (silica)
which feels very rough to the
touch
• called "scouring rushes" used for scouring pots and
pans before scouring powder
and pads were known.
Vascular Plants with Seeds
These
plants do not require water for
sexual reproduction.
They reproduce by seeds rather than
spores.
Seeds are multicellular and contain a
young plant called an embryo.
Vascular Plants with Seeds
Two main groups of seed plants:
Gymnosperm
 Angiosperms

gymnosperms
• the seed plants that do not first produce a
flower before the seed
• means "naked seed" - produce seeds not
covered by the walls of an ovary
• do not form flowers or fruits
• produce cones or cone-like structures
gymnosperms
angiosperms
• The Flowering Plants – means “covered
seed”
• All have seed enclosed in a fruit
• All have flowers (not all are colorful
blossoms - corn tassels and catkins of oak
trees)
angiosperms
Gymnosperms vs Angiosperms