Horticulture Science Lesson 6 Classifying Ornamental Plants

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Horticulture Science Lesson 6Classifying
Ornamental Plants
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Interest Approach
Ask students to list as many plants as they
possibly can in two or five minutes. (An
interesting side activity is to ask them to list
as many animals as possible in one minute. Notice
that many more animals are listed on most student
papers.) Begin a discussion on what types of
plants were listed. Are they monocots or dicots,
deciduous or evergreen, annual or perennial?
(With the side activity, are they mammals,
birds, reptiles, amphibians, or fish?)
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Interest Approach cont.
Why do students know more animals than plants?
Why are students better able to classify animals
than plants? Is it because of parents lack of
plant knowledge or weaknesses in the educational
system? Go around the room from student to
student asking each to name one plant with which
he or she is familiar. Immediately classify each
plant as a fern, gymnosperm, or angiosperm (and
whether each angiosperm is a monocot or a
dicot). After each student has had a turn,
allow the class to make observations as to
which types of plants are the most familiar and
common.
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Student Learning Objectives

• Discuss the classification and naming of plants.
• Distinguish the major groups of plants.
• Contrast the classification of plants by life
  cycle.

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Terms

• angiosperms
• annuals
• biennials
• binomial nomenclature
• bryophytes
• conifer
• cotyledon
• cultivar

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Terms

• deciduous
• dicots
• evergreen
• ferns
• genus
• gymnosperms
• herbaceous
• monocots

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Terms

• morphology
• perennial
• species
• taxonomy
• variety
• vascular plants

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How are plants classified and named?

• The branch of biology that deals with identifying
  and naming organisms is taxonomy.
• Plants are classified based on the similarities
  of their characteristics.
• Plant taxonomists compare flowering patterns,
  stem and leaf structures, life cycles, genetic
  similarities, and many other characteristics in
  determining which plants are the most closely
  related.

• The study of the form or shape of organisms or
  parts of an organism is called morphology.

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How are plants classified and named?

• Taxonomists use categories to group the plants.
• The categories, from general to specific, are
  Kingdom, Division (Phylum), Class, Order, Family,
  Genus, Species, Variety, and Cultivar.
• All plants are in the Kingdom Plantae. Vascular
  plants (plants with tissue specialized for
  conducting materials) are in the Division
  (Phylum) Tracheophyta.

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How are plants classified and named?

• Plants are named using a system called binomial
  nomenclature.
• This classification system was developed by
  Carolus Linnaeus and uses Latin terms as
  scientific names for plants.

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How are plants classified and named?

• Even though each plant is given at least seven
  names, it is commonly referred to by two
  scientific names.
• The two names used for the scientific names of
  plants are the Genus name, which is always
  capitalized, and the species name, which is
  always lower case (e.g., Liriodendron tulipifera).

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How are plants classified and named?

• The genus is a group of plants that are very
  similar to each other.
• The species is a group of plants that are so
  similar that they usually mate freely with each
  other in the wild.
• Plants are also called by common names, but those
  names are specific and are based on language and
  geographic location.

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How are plants classified and named?

• For instance, Liriodendron tulipifera is known in
  the United States as the yellow poplar, tulip
  poplar, tulip magnolia, whitewood, and tulip
  tree.
• Although the tulip tree may be known by many
  common names in the United States, the plant is
  recognized as Liriodendron tulipifera everywhere
  on Earth.

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How are plants classified and named?

• Sometimes cultivated plants within a species show
  a significant difference from other plants in the
  species.
• These plants are called a variety. The difference
  is inherited from the previous generation through
  sexual reproduction.
• The variety is written in lower case, underlined
  or italicized, and follows the specific epithet.
• A variety of Colorado spruce with bluish needles
  is written as Picea pungens var. glauca or
  Picea pungens glauca.

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How are plants classified and named?

• Another group important to the horticulture
  industry is cultivar.
• Cultivars have distinguishing characteristics
  from the other plants in the species, but
  cultivars do not transfer those characteristics
  to offspring
• through sexual reproduction.

• Cultivars are propagated by selective
  hybridization or asexual means.
• A cultivar of red maple is written as follows
  Acer rubrum, also known as October Glory.

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What are some ways that we can put plants into
groups?

• The plant kingdom has become successful all over
  the Earth by adapting to a wide variety of
  different conditions and niches.
• The following are some of the major plant groups.

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What are some ways that we can put plants into
groups?

• Bryophytes are plants that are classified in the
  Phylum Bryophyta.
• These are nonvascular plants such as mosses and
  liverworts.
• They tend to live in damp places and are very
  limited in size due to the lack of conducting
  tissue.

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What are some ways that we can put plants into
groups?

• Ferns are vascular plants that reproduce by
  spores.
• Some people call them the amphibians of the plant
  world because they are dependent on water for
  their sperm to swim through during reproduction.
• Ferns have no true leaves but have fronds, which
  have a double purpose of food production and
  spore formation.

• Fronds tend to unfold from the center of the
  plant, causing the newest fronds to be called
  fiddlehead.

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What are some ways that we can put plants into
groups?

• Gymnosperms are plants that reproduce with seeds
  that lay naked on scales.
• Most gymnosperms reproduce using a structure
  called a cone.
• Any gymnosperm that reproduces by cone is called
  a conifer.

• Examples include pines, spruces, and cedars.

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What are some ways that we can put plants into
groups?

• Conifer leaves are specialized to be either
  needles or scales.
• Most conifers are evergreen, holding leaves all
  year.

• But some are deciduous, dropping leaves in the
  winter.
• An example is the bald cypress.

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What are some ways that we can put plants into
groups?

• Angiosperms are seed plants whose seeds develop
  within a fruiting body.
• Angiosperms all reproduce by flowers, although
  many flowers are very small and not showy.
• So if any plant has flowers, it is in the
  Angiosperm group.
• There are two types of Angiosperm.

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What are some ways that we can put plants into
groups?

• Monocots are plants that have a single cotyledon
  or seed piece.
• Monocots have flower parts in multiples of three,
  parallel venation on their leaves, stems with
  scattered vascular bundles, and narrow leaves.
• Examples include grasses, sweet corn, and lilies.

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What are some ways that we can put plants into
groups?

• Dicots are plants with two cotyledons in their
  seeds.
• They have flower parts in multiples of four or
  five, netted veins, and stems that are organized
  in a ring pattern.
• They have broad leaves and include roses,
  petunias, and geraniums.

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What are some ways that we can put plants into
groups?
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How are plants classified by life cycle?

• Plants are often classified based on their life
  cycles.
• Gymnosperms and angiosperms reproduce by seed, of
  course, but there are different strategies for
  passing on that seed to future generations of
  plants.

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How are plants classified by life cycle?

• Plants that complete their life cycle within one
  year or one growing season are called annuals.
• Seeds of annuals germinate, produce leaves and
  roots, flower, produce seed, and then die, all in
  less than a year.

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How are plants classified by life cycle?

• Many of our crops and garden plants are annuals.
• Corn, soybeans, rice, wheat, potatoes, and
  tomatoes are examples of annual food crops.
• Petunias, impatiens, marigolds, and zinnias are
  examples of garden annuals.
• Many plants that are considered weeds (i.e.,
  ragweed, pigweed, lambsquarter, and crabgrass)
  are annuals, too.

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How are plants classified by life cycle?

• Biennials are plants that normally require two
  growing seasons to produce flowers and seed
  before dying.
• In the first growing season, biennials grow
  vegetatively.
• In the fall, they go dormant and rest until the
  following spring.
• During the winter months, they receive a required
  cold treatment.

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How are plants classified by life cycle?

• Growth is resumed in the spring of the second
  season.
• The plants bolt, flower, produce seed, and die.
• This group of plants is fewer in number than the
  other two groups.
• Some examples include hollyhock, Sweet William,
  parsley, beets, and carrots.

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How are plants classified by life cycle?

• Technically, a perennial is a plant that has a
  life cycle of more than two growing seasons.
• It may take perennial plants a few years to many
  years to reach reproductive maturity.
• Woody perennials may flower and produce seeds
  every year for many years.
• They may be woody like trees and shrubs or
  herbaceous.

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How are plants classified by life cycle?

• The shoots of herbaceous perennials typically die
  back to the ground each winter.
• The roots and crowns of herbaceous perennial
  plants survive and send up new shoots in the
  spring.
• Strawberries and asparagus are herbaceous
  perennials.

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How are plants classified by life cycle?

• Woody perennial plants produce secondary growth
  that persists year after year.
• Secondary growth gives the plants the ability to
  grow in girth and height.
• During the winter months, they go dormant.
• Plant growth resumes in the spring.
• Examples of woody perennial plants include
  apples, maples, oaks, almonds, and oranges.

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How are plants classified by life cycle?
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Review/Summary

• How are plants classified and named?
• What are some ways that we can put plants into
  groups?
• How are plants classified by life cycle?