DEPARTMENT OF

PRIMARY INDUSTRIES

Plant Biology

Weed Spotter training – Module 2

NAMEWeed Alert Contact Officer, CATCHMENT

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 don’t. 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.

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

Biological system of classification

The rank order of taxa used for plants is:example: Blue Gum

Kingdom PlantaePhylum Magnoliophyta

Class MagnoliopsidaOrder Myrtales

FAMILY Myrtaceae Subfamily Leptospermoideae

GENUS EucalyptusSPECIES E.

globulusHybrids, subspecies, varieties etc.

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

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

ActivityPlant Naming

The Plantae kingdom is divided into;

Major plant groups

non-vascular plants(liverworts and mosses)

seed bearing vascular plants (cycads, conifers and other gymnosperms

All flowering plants)

spore bearing vascular plants

(ferns, clubmossesand horsetails)

• Non-vascular plants, do not have vascular tissue and include; Algae Bryophytes;

- liverworts- hornworts- mosses

• They do not have roots, stems or leaves

Non-vascular plants

Moss (Bryophyta)Hornwort

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

• Equisetum (Horsetail)

Spore-bearing vascular plants

Seed-bearing vascular plants

• Gymnosperms – seeds are unenclosed on the scales of a cone or similar structure

cycads conifers NOT palms

these are Angiosperms

• 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, palmsPhoto: D Greig

Seed-bearing vascular plants

Bear-skin fescue

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

Angiosperms – flowering plants

Activity

Plant Classes

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

FABACEAE

ASTERACEAE

ASTERACEAE – daisy family

Black knapweed

Centaurea nigra

State Prohibited Weed

• 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

ASTERACEAE

• Orange Hawkweed (Hieracium aurantiacum)

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 grassNassella charruanaState Prohibited Weed

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 BroomCytisus multiflorusVictorian Alert Weed

Acacia seed pods

FABACEAE – pea family

• Flowers consist of 5 petals– 1 Standard– 2 Wing– 2 Keel

• Stamens are in the Keel

Photo: M D Crisp

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

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

Questions?

Acknowledgements

Information sourced from:

Knox, Ladiges and Evens, 1994. BiologyMcGraw-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