Plant Identification

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Plant Identification

• Roots, Stems, Leaves and Flowers are the
  Criteria.

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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.

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Terminology

• In order to be able to identify a plant and put
  it in the right family, you need to know the
  terminology to use.

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Plant Identification

• You have two main categories of plants.
• Monocots grasses, grain crops, lilies,
  gladiolas, and palm trees

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Plant Identification

• Dicots - most of the other plants such as the
  shrubs, trees, and flowers.

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Plant Identification

• The following sections (roots, stems, leaves and
  flowers) will show you how to use these for plant
  identification purposes.

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Roots

• The type of root will normally help you identify
  the plant. It will place the plant into a monocot
  or dicot category.

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Types of Roots

• Tap Root
• Have a main central root and may have some
  lateral branching
• E.g. Carrots

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Types of Roots

• Penetrate the soil to various depths - some only
  a few feet, others like the mesquite to as deep
  as 114 ft.

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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

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Types of Roots

• This root system can effectively prevent any
  other plant from becoming established ex
  grasses - idea of a healthy lawn is to compete
  with weeds

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Types of Roots

• Adventitious Buds - commonly develop on stems or
  roots - ex stolons and rhizomes (Bermuda grass,
  cherry tree, Sumac and raspberry suckers)

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Types of Roots

• Prop Roots - augment regular roots for anchorage
  aid - ex corn - roots come out above soil and
  help hold plant up

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Types of Roots

• Aerial Roots - extend down from the branches into
  the soil - ex banyan trees
• Pneumatophores- stick up from the mud for the
  purpose of absorbing oxygen ex cypress and
  mangrove

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Types of Roots

• Mycorrhizal fungi roots - form associations with
  soil fungi and act as root hairs increasing the
  absorption of water and minerals (symbiotic
  relationship - mutually beneficial) found on
  trees in temperate forests such as pines and also
  on ferns, lettuce, white clover, perennial rye
  and orchids

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Types of Roots

• Haustorial - parasitic roots which not only
  anchor but also penetrate into the hosts vascular
  system for water and nutrients ex mistletoe

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Types of Roots

• Storage roots - starch and other molecules are
  stored for growth or flowering needs (ex
  carrots, beets and turnips)

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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.

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Why Different Types of Roots

• All plants are in competition with each other for
  food and nutrients
• By having different types of roots, the plants
  can reach different depths in the soil and still
  live side by side with other plants

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Roots from Seeds Monocot vs. Dicot

• Tap Root
• Seeds contain an undeveloped plant (embryo)
• Seed germination - embryonic root (radicle) grows
  by dividing and elongation of cells

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Roots from Seeds

• Forms one primary root
• Ex dicots (two leaves emerge from embryo), beans

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Roots from Seeds cont.

• Fibrous root
• Embryos of grasses have a single radicle (root
  shoot)
• Also has other embryonic roots (seminal roots)
  forming just above the radicle

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Roots from Seeds cont.

• All of these branch to form the fibrous root
• Ex monocots (one leaf emerges from embryo)

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Dicot Seed
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Monocot Seed
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Stems

• Flowering plants - divided into two groups,
  monocots and dicots - stems have major
  differences in arrangement, distribution of
  tissues and appearance.

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Stems

• For identification type of stem (woody or
  herbaceous), monocot or dicot, has pubescence
  (hair) or not (glabrous), shape of stem (square
  round), or contains glands.

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Monocot stem
Dicot stem
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Mature Structure of Woody vs Herbaceous Stems

• Herbaceous stems
• Lack secondary growth - because plants only live
  one year/growing season (annuals)

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Mature Structure of Woody vs Herbaceous Stems

• Stems remain soft and flexible.
• Buds lack protective scales (dont need to
  survive harsh conditions)

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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

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Specialized Stems

• Adventituous stems can be either rhizomes or
  stolons.

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Specialized Stems

• Rhizomes - underground horizontal stems (ex
  perennial grasses, bamboo) - may also serve as a
  storage function (irises) will grow a plant and
  roots at a node.

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Specialized Stems

• Stolons - runners - usually above ground,
  horizontal stems (really elongated internodes)
  will grow a plant and roots at a node - ex
  strawberries

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Specialized Stems

• Tubers - several internodes at the end of an
  underground rhizome (ex potatoes) - eyes are
  axillary buds where the tuber will grow a plant

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Specialized Stems

• Bulbs - large bud with small stem at lower end -
  storage in the form of numerous, fleshy leaves -
  ex onion, lily, tulip
• Corms - look like bulbs, but are mostly stem
  tissue with a few, papery leaves on the outside -
  ex gladiolus, crocus

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Leaves

• Leaves are used as part of the identification
  process along with the roots and stems.
• Look of the leaf (margins, venation, and shape),
  arrangement and whether it is monocot or dicot.

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Leaves

• Leaves may contain pubescence, glands or thorn
  like projections.
• All of these points are considered when using a
  leaf for identification.

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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

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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

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Where leaf would be attached to the branch or
stem at the node.
Petiole
Veins
Leaf Blade
Dicot Leaf
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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

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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

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Monocot Leaf
Blade
Sheath
Node
Collar
Auricle
Stem
Ligule
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Parts of a Monocot Leaf

• Auricle small appendages that extend out and
  sometimes around the stem found at the junction
  of the blade and sheath can be clasping or non
  clasping appendages

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Parts of a Monocot Leaf

• Collar area between the leaf blade and sheath
  auricles and ligules are on the inside of this
  area

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Picture showing parts of a grass plant.
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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

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Two Types of Leaves

• Simple leaves composed of a single leaf and a
  petiole

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Blade
Petiole
Simple Leaf
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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

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Two Types of Leaves

• Palmately Compound (chestnut) the lobes or
  divisions come together and are attached at one
  place at the base

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Leaf Blade
Palmately Compound Leaf
Petiole
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Two Types of Leaves

• Pinnately Compound compound leaf with the
  leaflets on two opposite sides, but off of one
  node ex ferns, ash, hickory

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Leaflets
Leaf Blade
Pinnately Compound Leaf
Petiole
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Leaf Arrangement

• Monocots have only one type of arrangement
  leaf comes off of a node ex grasses and grain
  crops

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Leaf Arrangement

• Dicots flowering plants
• Alternate one leaf per node
• Opposite two leaves per node
• Whorled three or more leaves per node

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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

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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

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Arrangement of Veins

• Netted veins are large and small the small
  ones connecting to each other to form a net
  mostly dicots

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Arrangement of Veins

• Pinnately veined with one larger midvein and
  smaller veins coming off along its length
  mostly dicots

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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

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Parallel Veins
Netted Veins
Palmately Veined
Pinnately Veined
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Monocot Leaf -Vein Arrangement
Vein
Dicot Leaf Vein Arrangement
Smaller lateral vein
Midvein
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Leaf Modifications

• Tendrils typically at the end of a compound
  leaf enables plant to climb ex pea

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Modifications

• Stipules occur at node where normal or true
  leaves arise from stem are small leaf like
  structures at the base of petioles may be leaf
  -like or spines (ex locust)

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Modifications

• Spines modified leaves ex cactus
• Awn on reproductive structure in grasses
  extension of the lemma portion of the flowering
  structure

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Modifications

• Bracts floral leaves that form at the base of a
  flower or flower stalk
• Cotyledon the embryo leaf in a seed - first
  leaf of a seedling used for food storage

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Flowers

• Petals are highly colored portions of the
  flower.
• May contain perfume (rose) or nectar glands to
  attract pollinators.
• Number of petals on a flower is often used in the
  identification of plant families and genera.

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Flowers

• Dicots have sepals and/or petals in multiples of
  four or five
• Monocots have sepals in multiples of threes

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Parts of a Flower
Sepals
Petals
Stamens (anther filaments)
Pistil (stigma,style ovaries)
Pedicel
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Parts of a Flower
Pedicel
Sepals
Receptacle
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Types of Inflorescence (Flowers)

• Raceme inflorescence with the flowers single on
  pedicels (stems) arranged along an elongated
  stem (rachis this is the stem that is between
  the flowers) alternate oldest are at the
  bottom and the youngest are at the top. Ex
  snapdragon, foxglove

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Types of Inflorescence (Flowers)

• Umbel flat-topped inflorescence with the rachis
  non-existent. Ex wild carrot, dill

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Foxglove
Snapdragon
Raceme
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Dill
Umbel
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Types of Inflorescence (Flowers)

• Spike type of inflorescence with the flowers
  sessile (without a stalk) along the rachis. Ex
  gladiolus
• Head a dense cluster of sessile or nearly
  sessile (no stalk) flowers on a very short
  rachis. Ex sunflower, clover

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Spike
Gladiolus
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Clover
Sunflower
Head
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Types of Inflorescence (Flowers)

• Panicle inflorescence with two or more flowers
  on each branch which are attached to a rachis
  (elongated stem). Ex wild oats, downy brome
• Corymb is made up of florets whose stalks and
  pedicles are arranged at random along the stalk
  in such a way that the florets create a flat,
  round top. Ex yarrow

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Wild Oats
Downy Brome
Panicle
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Corymb