Plant Classification

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Plant Classification
Quiz 12C
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.
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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?
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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.
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The 3 Major categories of plants
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Non-vascular plants
Phylum Bryophyta
moss
liverwort
hornwort
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Non-vascular plants
These plants are called bryophytes. Phylum
Bryophyta (means mosslike plant)
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Non-vascular plants

• Water and other materials are transported by
  diffusion.
• Fairly short.

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Non-vascular plants

• Sometimes have parts that look like roots,
  stems, or leaves, but there is no vascular tissue
  so they dont have roots, stems, or leaves.
• Live near water or shady places.

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Just because a plant has the word moss in its
name, doesnt make it moss. Examples

• Irish moss (algae)
• Reindeer moss (lichen fungus algae
• Spanish moss (flowering plant)

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Irish Moss
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Reindeer Moss
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Spanish Moss
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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
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Parts of a moss plant
Leafy Shoot
Rhizoids
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Moss Leafy Shoot
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Life Cycle of Moss
Alternation of Generations

• Sporophyte Generation produces spores (asexual)
• Gametophyte Generation produces gametes (sexual)

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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)

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Life Cycle of Moss
Sporophyte Generation

1. Zygote grows into a stalk with a capsule which
   produces spores
2. When mature the cap comes off and spores disperse
3. Spore grows when environmental conditions are
   right
4. First grows into a cellular filament called a
   protonema
5. Protonema then forms the leafy shoots and rhizoids

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Life Cycle of Moss
Protonema
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Moss
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Moss Capsule
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Liverworts
Liver Plant
Marchantia a common liverwort with a y-shaped
thallus
Have splash platforms which look like little
umbrellas
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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

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Phylum Pterophyta

• Vascular Plants Without Seeds

Ferns
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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

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Parts of a fern

• Fronds leaves
• Rhizome a creeping or underground stem, which
  produce roots
• Sori groups of spore-bearing sporangia (means
  a heap)

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Fern Sori
Sori may be round, kidney-shaped, oblong, linear,
curved, or star-shaped.
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Sporophyte Generation of Ferns
A new ferns life cycle typically begins in July
with the appearance of sori on the undersurface
or along the margins of a frond.
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Sporophyte Generation

• Sori appear on the underside of a frond.
• Sori first open and discharge millions of spores.

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Gametophyte Generation
Spore develops into a tiny green, heart-shaped
structure called a prothallus.
Seldom seen, only 1 cell layer in thickness.
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Gametophyte Generation
The underside of the prothallus develops
archegonia and antheridia
Antheridia near the point (sperm)
Archegonia at notched end (ova)
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Gametophyte Generation
Sperm are released from the antheridia and swim
to the ovum at the bottom of the archegonia.
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Sporophyte Generation
Zygote matures and sends the first leaf up and
the first root down.
The first leaf is often a fan-shaped blade.
The second leaf is usually a fiddlehead, a coiled
young leaf. Some fiddleheads are edible and used
in salads.
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(No Transcript)
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Fern Alternation of Generation Facts
Ferns usually require 3-7 years to reach
reproductive maturity.
Fern plants (sporophytes) live for several years
and produce new fronds each year
Dominant generationSporophyte
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Fern Alternation of Generation Facts
Protellia (gametophytes) only live 3-7 weeks, in
which time they produce the archegonia and
antheridia.
Dominant generation Sporophyte
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Other seedless vascular plants club moss,
whiskfern horsetail
club moss
whiskfern
horsetail
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club moss
club mosses (also called "ground pine" because
they grow along the ground in temperate regions)
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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.

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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.

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Vascular Plants with Seeds
Two main groups of seed plants

• Gymnosperm
• Angiosperms

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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

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gymnosperms
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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)

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angiosperms
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Gymnosperms vs Angiosperms