plants. plant identification many things are taken into consideration when trying to identify a...
TRANSCRIPT
Plants
Plant Identification
• Many things are taken into consideration when trying to identify a plant.
• Roots, stems, leaves and flowers will help in the identification process.
Plant Identification
• You have two main categories of plants.–Monocots – grasses, grain crops, lilies,
gladiolas, and palm trees
Plant Identification
–Dicots - most of the other plants such as the shrubs, trees, and flowers.
Types of Roots
• Tap Root–Have a main central root and
may have some lateral branching–E.g. Carrots
Types of Roots
• Fibrous–Have many roots of equal size and a lot
of lateral branching–Fibrous roots are generally much more
diffuse and closer to the surface
Types of Roots
• Nitrogen fixing roots - members of the Leguminosae family (alfalfa, peas and clover) have a bacteria that infects their roots and forms nodules. The bacteria are able to fix atmospheric nitrogen, to a form, that the plant can use.
Dicot Seed
Monocot Seed
Mature Structure of Woody vs Herbaceous Stems
• Herbaceous stems–Lack secondary growth - because
plants only live one year/growing season (annuals)
Mature Structure of Woody vs Herbaceous Stems
• Woody stems–Plants living and growing over multiple
seasons have secondary growth (xylem, phloem) increasing diameter of the stems
Parts of a Dicot Leaf
• Leaf blade – expanded, usually flat portion of a leaf – contains chloroplasts
• Petiole – connects the blade of a leaf to a stem or branch – holds leaf up for better air flow and to catch the light
Parts of a Dicot Leaf
• Veins – threads of vascular tissue (xylem & phloem)
• Node – place on a stem where leaves or branches normally originate
• Stem – used for support of leaf
Leaf Blade
Petiole
Veins
Where leaf would be attached to the branch or stem at the node.
Dicot Leaf
Parts of a Monocot Leaf
• Node – where leaf arises or originates from
• Blade – leaf blade – flat upper portion of leaf
• Stem – used for support of leaf, inflorescence, and seed heads
Parts of a Monocot Leaf
• Sheath – part of leaf that holds leaf to stem – encases stem
• Ligule – membrane-like tissue extending up from the sheath (on inside) – keeps dirt and moisture out – clear membrane on leaf where attaches to stem
Sheath
Blade
Node
Collar
Auricle
Ligule
Stem
Monocot Leaf
Differences Between Monocot and Dicot Leaves
• Monocots – blade like leaf blade – wrap around the stem – no petiole – have main vascular bundles running parallel along length of leaf
• Dicots – Have both a leaf blade and a petiole – single midrib (Vascular bundles) with branches
Two Types of Leaves
• Simple leaves – composed of a single leaf and a petiole
Simple Leaf
Blade
Petiole
Two Types of Leaves
• Compound leaves – are composed of a blade that includes several leaflets and a petiole – also contain a rachis (connects leaflets to the petiole) – two types:
Two Types of Leaves
–Palmately Compound – (chestnut) – the lobes or divisions come together and are attached at one place at the base
Palmately Compound Leaf
Leaf Blade
Petiole
Two Types of Leaves
–Pinnately Compound – compound leaf with the leaflets on two opposite sides, but off of one node – ex: ferns, ash, hickory
Pinnately Compound Leaf
Leaf Blade
Leaflets
Petiole
Leaf Arrangement
• Monocots – have only one type of arrangement – leaf comes off of a node – ex: grasses and grain crops
Leaf Arrangement
Dicots – flowering plantsAlternate – one leaf per nodeOpposite – two leaves per nodeWhorled – three or more leaves per
node
Leaf Arrangements
Whorl – look like helicopter blades – ex: Bedstraw
Alternate – one on each side of the stem, are not opposite of each other but every other one
Opposite – one on each side of the stem and opposite of each other
Arrangement of Veins
• Four types of vein arrangements:–Parallel veins – veins are small
and run more or less parallel – most are long and narrow – ex: Buckhorn Plantain, grasses and Iris – mostly monocots
Arrangement of Veins
–Netted veins – are large and small – the small ones connecting to each other to form a net – mostly dicots
Arrangement of Veins
–Pinnately veined – with one larger midvein and smaller veins coming off along its length – mostly dicots
Arrangement of Veins
–Palmately veined- with two or more large veins arising at or near the base of the leaf blade (palm) – leaves are usually broad or fat – mostly dicots
Parallel Veins
Netted Veins
Pinnately Veined
Palmately Veined
Flowers
–Dicots –have sepals and/or petals in multiples of four or five–Monocots – have sepals in multiples of
threes
Angiosperms – flowering plants.Gymnosperms – cone bearing plants.
Parts of a Flower
Petals
Stamens (anther & filaments)
Pistil (stigma,style & ovaries)
Sepals
Pedicel
Sepals
Receptacle
Pedicel
Parts of a Flower
Types of Monocots and Dicots
Vascular Bundle of Monocots
• In monocots, the vascular bundles in the stem cross section are usually scattered or more complex of an arrangement as compared to dicots.
Vascular Bundle of Dicots
• The vascular bundles in the stem cross section of dicots are arranged in a circle, or ring.
Comparison of Plants
• Monocot is on the left– Oat plant
• Dicot is on the right– Bean plant
• Notice the difference in the two plants
Characteristics of Dicots
Characteristics of Monocots