What Is the Difference Between
Annuals, Biennials and Perennials?
• Plants are often classified based on their life
cycles.
• Even though gymnosperms and angiosperms
reproduce by seed, there are different
strategies for passing the seeds on to future
generations.
Corn – Zea mays
Annuals
• Plants grow from seed,
flower, produce new seeds
all in one season.
• It dies after producing new
seeds.
• Have an herbaceous stem –
green & fleshy.
– Ex. Impatiens, corn,
snapdragons.
See life cycle
Courtesy of Wm. C. Brown Publishers
Foxglove – Digitals purpurea
Biennials
• Plants that live for two
years, then flower and
die.
• Food is produced
during the first year,
flowers the second
year.
– Ex. Foxglove, carrot,
queen Anne’s lace.
See life cycle
Courtesy of Wm. C. Brown Publishers
Perennials
Bristlecone pine – Pinus
longaeva
• Plants that live for three or
more years
• Flower for a short time
• Do not die after flowering
• Can be herbaceous or
woody – having thick stems
made of wood
– Ex. Tulips, Kentucky bluegrass,
trees and shrubs
See life cycle
Courtesy of Wm. C. Brown Publishers
Back to Annuals
Germination----Growth---Flowering----Death
Back to Perennials
Germination---- Growth---Flowering----Dormancy
One or more flowering cycles
Back to Biennials
Germination---Growth---Dormancy---Growth---Flowering---Death
Season 1
Season 2
Courtesy of Interstate Publishing
What Are the Functions of a Plant’s
Roots?
• A plant’s health is directly related to its roots.
• Weak and diseased roots decrease a plant’s
health.
What Are the Functions of a Plant’s
Roots?
• Roots need to continuously grow in order to
stay healthy.
• This is why plants become pot-bound: the
roots start growing out of the pot because it is
too small.
A pot bound plant
in need of
transplanting
Courtesy of Delmar Publishing
Functions of a Root System
• 1. Absorb water and minerals
from the environment.
• 2. Anchor the plant in the
ground.
• 3. Store food that has been
made in the leaves by
photosynthesis.
– Can be used later by the plant to
grow and survive.
Taraxacum
officinale – the
common dandelion
Courtesy of Wm. C. Brown Publishers
What Are the Parts of a Root?
• When a seed germinates, the first structure to
appear is the root, or radicle.
• A. It becomes the primary root
– Usually the most important root in some plants.
• B. Other roots branch out from the primary
root; called secondary roots.
What Are the Parts of a Root?
Cotyledon
Courtesy of McGraw Hill
Radicle = Primary
root; notice all the
root hairs
What Are the Parts of a Root?
• C. The apical meristem, found at the root tip,
is where new cells develop.
– It is covered by the root cap – protects it from
damage as it passes through coarse soil particles.
Vascular
cylinder
(xylem &
phloem)
Epidermis
Apical
meristem
Root Cap
Courtesy of Dorling Kindersley, Inc.
Cortex
(food
storage)
What Are the Parts of a Root?
• D. The surface of the root is protected by skin
cells called the epidermis.
– Where water and minerals enter the root by osmosis
& diffusion.
– Can grow long, hair like projections called root hairs.
– They greatly increase the surface area of the root to
allow more water intake.
Courtesy of Delmar Publishing
Two Types of Root Systems
• Plant root systems are organized in two
basic ways; It has to do with primary and
secondary roots
• A. A root system comprising one main
primary root and many secondary roots
branching off the primary root is called a
taproot system
– Ex. Carrot, Parsnip, Oak
– Their roots reach far into the ground; they can
be several feet long
Examples of Taproots
Carrot
Beet
Sweet potato
Courtesy of Wm. C. Brown Publishers
Two Types of Root Systems
• B. A system which has no dominant
primary root but is made of many primary
and secondary roots of similar size is called
a fibrous root system
• Ex. Grasses, Magnolia, Rhododendron,
Euonymus
• The roots are smaller, shorter and more
compact; They usually never grow below
the first 6-12 inches of soil
– These roots form a large network underground
Fibrous Root System of Grass
Courtesy of McGraw Hill
Publishing
What Does a Healthy Root System
Look Like?
• A healthy root system is white or nearly
white in color and smells fresh, or earthy.
• If roots are black, brown, or dark orange
and smell rotten or sour, the root system
is having some problems.
• Watering a plant properly is one of the
most important ways to keep the root
system healthy.
What Does a Healthy Root System
Look Like?
• If the plants are grown in pots, be sure that
there are drainage holes in the bottom to
allow excess water to drain.
– Soak the pot until the growing medium is
saturated and water drips out of the drainage
holes.
– This encourages the roots to grow through the
entire pot.
What Are the Functions of a Stem?
• Stems have many important jobs in a plant.
• They are responsible for the size and shape of
a plant.
• Some are made of wood and some are
herbaceous.
• There are four functions of the stem.
Functions of a Stem
• 1. Stems support the leaves.
– Able to stretch the leaves into the best
positions for catching sunlight.
• 2. Move water, minerals and food
through the whole plant.
• 3. Can also produced food through
photosynthesis.
– Not its main job, but will occur in plants
with small or no leaves.
Functions of a Stem
• 4. Store food that has been
manufactured by the plant.
Stems of
bamboo plant
Courtesy of McGraw Hill Publishing
What Are Some of the Structures on
the Outside of a Stem?
• There are many structures on the stem
which are very useful to us in identifying
plants.
– Sometimes it is easier to identify a plant by its
stem rather than its leaves.
• There are eight structures found on the
outside of a stem:
– 1. Terminal bud – contains apical meristem;
found at the tip of a stem; it increases the
length of a stem.
What Are Some of the Structures on
the Outside of a Stem?
• 2. Node – where the leaf and bud attaches to
the stem.
• 3. Internode – distance between two nodes;
tells how much the tree grew in one season.
What Are Some of the Structures on
the Outside of a Stem?
• 4. Lateral bud – also called the axillary
bud; develops into a leaf or flower.
• 5. Lateral and terminal buds are
protected by bud scales – helps the bud
survive harsh climate changes; when the
bud opens in the spring, the scales fall off
leaving a bud scale scar.
What Are Some of the Structures on
the Outside of a Stem?
• 6. Leaf scar – is the remains of the leaf after
it has fallen off of the tree; it is just below
the lateral bud.
– If you look closely at the scar, you can see the
remains of the vascular tissue (xylem &
phloem).
• 7. Lenticels – are small spots on the stem
that allow a stem to exchange gases (oxygen
& carbon dioxide) with the environment.
External Parts of a Stem
Terminal bud
Leaf scar with
vascular bundle
scars
Node – where
leaf & bud
attach
Lateral bud
Lenticel
Internode –
distance between 2
nodes
Bud scale scar
What Are Some of the Internal
Structures of a Stem?
• Inside of the stem, there are tissues that
are used for transport of materials
through the plants.
• Stem tissues are organized in one
of
the following ways:
– They are found in small bundles
throughout the stem.
• They look like smiley faces.
• Characteristic of monocots.
Courtesy of Corinne Banowski
scattered
Monocot bundle
What Are Some of the Internal
Structures of a Stem?
• They are also found in rings around the stem.
– They look like candy-corns.
– Characteristic of dicots.
– This is what gives the plant
• Determines the age of a plant.
Courtesy of McGraw Hill Publishers
Dicot bundle
annual rings.
What Are Some of the Internal
Structures of a Stem?
• There are three important tissues found inside
the stem:
• A) xylem – conducts the water and minerals
upward throughout the plant.
– Made of tube-like cells which grow together to
conduct liquids.
– Tends to be found closer to the center of the stem.
What Are Some of the Internal
Structures of a Stem?
• B) Phloem – conducts the food that is
produced in the leaf downward to the rest of
the plant.
– These cells also form tubes.
– Tends to be found towards the outside of the
stem.
What Are Some of the Internal
Structures of a Stem?
• C) Cambium – the tissue responsible for the
production of new xylem & phloem.
– Also increases the girth (width) of a stem.
– Generally found between the xylem and phloem.
Location of Vascular Tissues
Notice that
monocots do not
have cambium
Xylem
Phloem
Vascular Cambium
What Are Some Different Kinds of
Specialized Stems?
• We generally expect stems to be upright
and above ground; however there are
many stems that do not fit this mold.
• Some stems are modified to store food
or help the plant reproduce.
• Some stems grow beneath the soil
instead of above it.
• There are five types of specialized stems.
Five Types of Specialized Stems
1. Bulb
• A very short, flattened stem.
• Has several fleshy leaves.
• Tend to be found beneath the soil.
– Ex. Onion, garlic
Courtesy of McGraw Hill Publishers
Five Types of Specialized Stems
2. Corm
• A spherical structure similar to a bulb.
• Most of the corm is stem (unlike the bulb which
is mostly leaves).
– Ex. Gladiolus
Courtesy of McGraw Hill Publishers
Five Types of Specialized Stems
3. Rhizome
• A thick underground stem.
• Lies horizontally.
– Ex. Hosta,
– Mother-in-Law’s Tongue
Leaf
Scale like leaf at
each node
Courtesy of McGraw Hill Publishers
Adventitious
roots
Five Types of Specialized Stems
4. Stolon
• A horizontal stem.
• Lies above ground.
• Sometimes called runners.
• Tend to be involved in spreading the plant.
– Ex. Strawberries
Courtesy of McGraw Hill Publishers
Five Types of Specialized Stems
5. Tuber
• A rhizome with a tip that is swollen with
stored food.
– Ex. Potatoes
Courtesy of McGraw Hill Publishers
What Are the Main Parts of a Leaf?
• Leaves are the primary food producing organs
of a plant.
• They are designed to efficiently collect light
and use that light energy to produce food.
– Remember that this process is called
photosynthesis.
• There are several parts of a leaf:
Main Parts of a Leaf
• 1. Tip or apex – this is the top of the leaf; It
can be pointed, round, smooth, etc.
• 2. Margin – is the edge of the blade; This is
quite specific to each species of plant.
– Some are smooth, toothed, lobed or incised.
Main Parts of a Leaf
• 3. Midrib – the central vein running down the
center of the blade.
• 4. Veins – contain the xylem & phloem of the
plant.
– They can be parallel or netted in arrangement.
Main Parts of a Leaf
• 5. Base – is found at the bottom of the blade;
Like the apex, it can be round, heart shaped,
flat, etc.
• 6. Petiole – is known as the leaf stem; It is not
exactly like a stem, but it does hold xylem &
phloem; Holds the blade away from the stem.
Main Parts of a Leaf
• 7. Blade – the main collecting structure of the
leaf; Has a large, broad surface.
– Has many layers which help the plant move and
store photosynthetic materials and by-products.
Main Parts of a Leaf
Tip/Apex
Midrib
Blade
Margin
Leaf
Veins
Base
Petiole
Courtesy of Corinne Banowski
What Are Some of the Major Types
of Leaves?
• There are many different types of leaves.
• Some are adapted to hot, dry climates.
– They store water in their leaves or are
smaller in size.
• Some have very large blades to collect
maximum light in shady locations.
• Some plants have their blades broken
into many sections.
What Are Some of the Major Types
of Leaves?
• A leaf which has only one blade on its petiole
is called a simple leaf.
– Most plants have simple leaves.
Courtesy of Wm. C. Brown Publishers
What Are Some of the Major Types
of Leaves?
• When the blade is divided into three or more
sections, it is said to be a compound leaf.
– There are many different kinds.
Courtesy of Wm. C. Brown Publishers
Types of Compound Leaves
Odd
Pinnately
Compound
Even
Pinnately
Compound
Courtesy of Wm. C. Brown Publishers
Palmately
Compound
What Are Some Vein Patterns
Found in Leaves?
• Veins of flowering plants are found in several
patterns.
– Most patterns can be categorized into two main
groups.
– A. Parallel veins – found in monocots.
• None of the veins on the whole leaf will cross each
other.
• It may look like they fuse together at the top or bottom
of the blade.
What Are Some Vein Patterns
Found in Leaves?
• B. Netted veins – found in dicots.
– They connect & branch from each other.
– Some have several smaller veins branching out
of a dominant midrib.
• Known as pinnately netted.
– Other leaves have several dominant veins
(midribs) branching from the petiole.
• Known as palmately netted.
– A few have a spreading vein pattern called
dichotomous venation.
• Seen in the Ginkgo tree.
Types of Leaf Venation
Palmately Netted
Veins
Parallel
Netted Veins
Pinnately Netted
Veins
Courtesy of Wm. C. Brown and McGraw Hill Publishers
Dichotomous
Netted Veins
How Is A Leaf Organized?
• A leaf is organized to collect sunlight and
turn it, through photosynthesis, into
food.
• The leaf has many layers of tissue to
allow this to happen:
– 1. Cuticle – on top of the leaf is a waxy noncellular layer.
• Prevents water from escaping the leaf.
• It is usually very thick on plants in arid regions.
How Is A Leaf Organized?
• 2. Epidermis – the next layer of the leaf.
– Used for protection.
– Skin-like layer found on the top & bottom of
the leaf surface.
– May be one or more cell layers thick.
• 3. Palisade mesophyll – directly beneath
the epidermis.
– Standing on end & packed very tightly.
– Responsible for most photosynthesis.
How Is A Leaf Organized?
• 4. Spongy mesophyll – under the palisade
layer.
– Loosely packed cells.
– Have numerous air spaces which hold the raw
materials used and products of photosynthesis.
How Is A Leaf Organized?
• 5. Stomata – usually on the lower epidermis.
– Tiny holes for gas exchange; They can open &
close.
• 6. Guard cells – control the opening & closing
of the stomata.
– Found on either side of the stomata.
Internal Parts of A Leaf
Petiole
Blade
Cuticle
Upper Epidermis
Palisade Mesophyll
Vein
Spongy Mesophyll
Lower Epidermis
Courtesy of
Wm. C. Brown
Publishers
Air
Spaces Stomata
Stoma, singular
Guard Cell
Summary
•
•
•
•
How is a blade different from a leaf?
Compare a midrib to a vein.
What is the edge of a leaf called?
How is a simple leaf different from a
compound leaf?
• Can you give an example of a simple or
compound leaf?
• What are the four types of venation
within the leaf?
Summary
• What protects the leaf on the outside? (It
is a waxy coating).
• What is the function of the epidermis?
• Compare the palisade layer with the
spongy layer.
• What is the purpose of a guard cell?
• Where does gas exchange occur on the
leaf?
What Are the Parts of A Flower?
• Flowers are the most obvious part of most
plants.
• They are made of many intricate and
important parts.
• Most flowers contain male and female parts.
Courtesy of McGraw Hill Publishers
Parts of a Flower
• 1. Stamen – the male part of a flower;
Made up of two parts:
– Filament – stalk of a stamen; Holds up the
anther.
– Anther – sack-like portion containing the
pollen.
• Pollen – grain released by the flowers; Contains
the sperm.
– Flowers containing only stamens are called
staminate.
Parts of a Flower
• 2. Pistil – female part of the flower;
Made up of three parts:
– Stigma – sticky organ which receives the
pollen grains.
– Style – a rod shaped middle part; Similar to
the stalk of the stamen.
– Ovary – swollen base containing the eggs or
ovules.
– Flowers having only female parts are called
pistillate.
Parts of a Flower
• 3. Petals – the showy, colorful leaf-like
structures which often attract animals or
insects for pollination.
– When all the petals are fused together, it is
called the corolla.
• 4. Sepals – beneath the petals; More leaflike structures usually green in color
– Protect the flower before it opens.
– When all the sepals are fused together, it is
called the calyx.
Parts of a Flower
Stigma
Anther
Stamen
Style
Filament
Ovary
Petals
Sepals
Ovule
Pedicel
Stem of the flower
Courtesy of McGraw Hill Publishers
Receptacle
Swollen base
where are parts
attach
Pistil
What is the Purpose of a Flower?
• We use flowers for many practical purposes
like food, clothing and medicine; We also use
them for aesthetic purposes – to beautify our
homes.
• The main purpose of a flower is to reproduce
sexually with other flowers or with itself.
What is the Purpose of a Flower?
• The first step of reproduction begins with
pollination (the process of transferring pollen
to stigma), and there are two types:
What is the Purpose of a Flower?
• A) Cross-pollination is when the pollen of one
plant lands on the stigma of a different plant;
• Keep in mind that the plants must be of the
same species (for example, two dandelions)
What is the Purpose of a Flower?
• B) Self-pollination occurs when the pollen of
the anther lands on the stigma of the same
plant.
• Pollen is carried to plants by animals, wind,
gravity, water and many other methods.
What is the Purpose of a Flower?
• Once the pollen reaches the stigma, it starts
to grown down the style depositing the sperm
in the ovary.
• When the sperm and egg combine, it is called
fertilization.
Courtesy of Interstate Publishers
Pollination and Fertilization
This picture shows selfpollination (pollen is being
transferred from the anther to
stigma of the same plant)
Notice that one or more pollen
grains will start to grow a tube
down towards the ovary
The sperm nucleus will then fuse
with the nucleus of the egg(s)
(ovule).
Courtesy of McGraw Hill Publishers
What Are Some of the Different Types of
Flowers?
• Flowers come in many shapes, sizes and colors.
• Not all of them have all the structures mentioned
before.
What Are Some of the Different Types of
Flowers?
• A. Complete flowers have all the major parts:
stamens, pistils, sepals & petals.
• B. Incomplete flowers are missing one or
more of these major parts; for example a
flower could be missing sepals or pistils.
What Are Some of the Different Types of
Flowers?
• C. Perfect flowers have both stamens and
pistils on the same flower.
• D. Imperfect flowers are missing either the
stamens or pistils.
How is a Monocot Flower Different
From a Dicot Flower?
• A good way to tell the difference between a
monocot and a dicot is to look closely at the
flowers.
• Monocots have flower parts in multiples of 3
(3,6,9,12).
• Dicots have flower parts in multiples of 4 or 5
(4,12,16 or 5,10,15).
Summary
• What is the male part of a flower called?
• What are the two parts of the stamen and what
do they do?
• What is a pistil? And what are its three parts?
• What is a staminate flower? Is it perfect or
imperfect?
• How is the corolla different from the calyx?
• What part of the flower usually attracts
pollinators?
• How is pollination different from fertilization?
Summary
• What are some ways in which a plant can be
pollinated?
• What are the two types of pollination and how are
they different?
• Describe how the sperm gets to the egg of the
flower?
• Can you have a perfect, incomplete flower and why?
• Can you have an imperfect, complete flower and
why?
• How can you tell the difference between a monocot
and a dicot flower?