Plant Biology

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Plant Biology

• Weed Spotter training Module 2
• NAME
• Weed Alert Contact Officer, CATCHMENT

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The kingdoms of life

• Monera Prokaryotic cells without a nuclear
  membrane, mitochondria or chloroplasts. Includes
  bacteria and blue-green algae
• Protista mostly unicellular, eukaryotic
  organisms, some of which photosynthesise and some
  of which dont. Includes some algae
• Fungi multicellular organisms that gain
  nutrients by decomposing organic molecules from
  their surroundings
• Plantae (Plants) multicellular organisms that
  produce organic molecules via photosynthesis.
  (They produce their own nutrients)
• Animalia (Animals) multicellular organisms that
  gain their nutrients via ingesting other
  organisms for food.

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Biological system of classification

• Carl Linnaeus (1707-78) developed the biological
  system of classification
• Organisms are classified into groups with common
  characteristics (appearance)
• A group or species is called a taxon and is given
  a Latin name
• The system is a hierarchy with specified levels
  or ranks with species as the smallest unit

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Biological system of classification

• The rank order of taxa used for plants is
• example Blue Gum
• Kingdom Plantae
• Phylum Magnoliophyta
• Class Magnoliopsida
• Order Myrtales
• FAMILY Myrtaceae
• Subfamily Leptospermoideae
• GENUS Eucalyptus
• SPECIES E. globulus
• Hybrids, subspecies,
• varieties etc.

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Plant names

• The scientific or botanical name of each kind
  of organism consists of two parts based on the
  smallest ranks in the biological system genus
  and species
• The genus is the generic name and always starts
  with a capital letter
• The species is called an epithet and always
  starts in lower case
• Plants may be from different genus but share the
  same epithet. E.g. Eucalyptus gunnii and
  Nothofagus gunnii

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Plant names

• The scientific name is followed by an
• abbreviation of the name of the original
• author of the plants name (E.g. F Muell. means
  it was named by Baron Ferdinand Von Mueller)
• Common names are not governed by
• any rules and therefore a species can
• have more than one common name
• Example of a Weed Alert species
• State Prohibited Weed
• genus is Eichhornia
• species is crassipes
• common name is Water Hyacinth

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• Activity
• Plant Naming

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Major plant groups

• The Plantae kingdom is divided into

non-vascular plants (liverworts and mosses)
spore bearing vascular plants (ferns,
clubmosses and horsetails)
seed bearing vascular plants (cycads, conifers
and other gymnosperms All flowering plants)
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Non-vascular plants

• Non-vascular plants, do not have vascular tissue
  and include
• Algae
• Bryophytes
• - liverworts
• - hornworts
• - mosses
• They do not have roots, stems or leaves

Moss (Bryophyta)
Hornwort
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Spore-bearing vascular plants

• Have vascular tissue
• Produce spores, not seeds
• Have no flowers
• Include
• ferns
• horsetails (State Prohibited Weed)
• club mosses

Horsetails Equisetum species
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Spore-bearing vascular plants

• Equisetum (Horsetail)

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Seed-bearing vascular plants

• Gymnosperms seeds are unenclosed on the scales
  of a cone or similar structure
• cycads
• conifers
• NOT palms
• these are Angiosperms

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Seed-bearing vascular plants

• Angiosperms (flowering plants) classified into
  two major groups
• Monocotyledons (Monocots) are mainly non-woody
  plants with
• flower parts are in threes (3, 6, 9 etc)
• parallel leaf veins
• vascular bundles scattered in the stem
• an embryo with one seed leaf (cotyledon)
• a fibrous root system
• includes grasses, lilies, grass trees, kangaroo
  paws,
• orchids, palms

Photo D Greig
Bear-skin fescue
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Angiosperms flowering plants

• Dicotyledons (Dicots) are either woody or
  herbaceous with
• flower parts in fours or fives
• net like leaf venation
• vascular bundles in a ring
• an embryo with two seed leaves (cotyledons)
• a tap like root system
• includes magnolias, buttercups, daisies, roses,
• peas, acacias, banksias and eucalypts

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Angiosperms flowering plants
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Activity Plant Classes
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Common plant families

• There are many plant families each with their own
  similar characteristics
• If you can recognise some of these
  characteristics then it can help you identify a
  plant
• Some common families include
• Asteraceae
• Poaceae
• Fabaceae
• Rosaceae

ASTERACEAE
FABACEAE
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ASTERACEAE daisy family

• Flowers that are clusters of smaller flowers
• They are successful weeds because
• many flowers in one is a successful
• reproductive strategy
• they set a lot of seed
• they have successful dispersal mechanisms
• such as wind (fluffy seed)
• they are either annuals or biennials
• so can reproduce quickly
• Includes daisies, thistles and everlastings

Black knapweed Centaurea nigra State Prohibited
Weed
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ASTERACEAE

• Orange Hawkweed
• (Hieracium aurantiacum)

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POACEAE grass family

• A big family, with over 600 genera
• Flowers are small, and sit together with two
  enclosing bracts known as florets
• One or more florets make a spikelet
• They are successful weeds as
• they are wind pollinated
• they set lots of seeds
• many are annuals and can
• set seed in a short season

Lobed needle grass Nassella charruana State
Prohibited Weed
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FABACEAE pea family

• Flowers are distinctive with 5 petals
• Fruit is always a pod that is dry at maturity and
  splits along both sides to release the seeds
• The leaves are simple or
• compound usually with stipules
• Includes herbs, shrubs, trees
• and climbers

White Spanish Broom Cytisus multiflorus Victorian
Alert Weed
Acacia seed pods
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FABACEAE pea family

• Flowers consist of 5 petals
• 1 Standard
• 2 Wing
• 2 Keel
• Stamens are in the
• Keel

Photo M D Crisp
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ROSACEAE

• 100-200 genera
• Mostly diagnosed by the fruit structure
• Small fruit (blackberry, strawberries etc.)
• Fruit with 5 capsules/cores (apples, pears etc.)
• Fruit as a single drupe (peaches, plums etc.)
• Can spread by canes (blackberry) or by birds or
  foxes eating the fruit or seed

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Key words

• Genus groups of species that have similar
  characteristics
• Species basic category of classification,
  related individuals that can breed within
  themselves
• Non-vascular lacking vascular tissue (for
  example water transport vessels)
• Gymnosperms a plant with seeds that are not
  enclosed in an ovary
• Angiosperms flowering plants (largest phylum of
  living plants)
• Monocots flowering plants that have a single
  seed leaf (cotyledon)
• Dicots flowering plants that have two seed
  leaves (cotyledons)
• Florets a small or reduced flower, usually
  enclosed in bracts (as in grasses)
• Spikelets a spike made up of one or more
  florets
• Stipules small appendages at the base of a leaf
  stalk
• Stamens pollen bearing part of a flower
• Simple has one main leaf, may have lobes but
  they do not reach the main vein
• Compound compound leaf has many leaflets coming
  off the main vein

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• Questions?

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Acknowledgements

• Information sourced from
• Knox, Ladiges and Evens, 1994. Biology
• McGraw-Hill Book Company
• Environmental weed training notes 2002,
  Department of Natural Resources and Environment,
  Victoria
• Line drawings by Kristy Roche, DPI
• Thank you for participating