Classifying Ornamental Plants
Suppose you were walking through the woods and stumbled upon an unusual plant. What would you call it? Would you know how to classify it? Could
you identify its characteristics? These are questions many taxonomists
ponder when labeling a new plant.
Take a couple of minutes and list as many plants as you possibly can. Let’s classify them as deciduous (loose their leaves) or coniferous (remain as evergreens).
Now list as many animals as you can. Can you classify them as birds, reptiles, amphibians, insects, fish, or mammals?
Why do you know more about animals?
Student Learning Objectives
1. Describe the system used for naming and classifying plants
2. Identify the major groups of plants 3. Describe the differences between
annuals, biennials and perennials 4. Understand how this information is
important to the Horticultural industry
Terms to Know Angiosperm Annuals Biennials Binomial nomenclature Bryophytes Conifer Cotyledons Deciduous Dicots
Evergreen Ferns Genus Gymnosperms Herbaceous Monocots Perennials Species Woody
How Are Plants Named and Classified?
Plants are classified by the similarities of their characteristics.– Taxonomists compare flower patterns,
stem and leaf structures, life cycles, genetic similarities and many other characteristics.
They are then grouped in specific categories, or taxas:
Kingdom Plantae
Phylum (Division) Magnoliophyta
Class Liliopsida
Order Cyperales
Family Poaceae
Genus Triticum
Species aestivum
*Sample classification of bread wheat
Categories/Taxas Example*
Botanists call plants by their last two taxas – genus and species– This system is known as binomial
nomenclature (two-word naming system)– Developed by Carl Linnaeus– Uses Latin for three reasons:
Universal (known by all scientists) Very descriptive Unchanged (contains no slang words)
– Genus is capitalized; Species lower case Ex. Triticum aestivum
Cultivars In the Horticulture
industry, we usually use cultivar names as well. Ex;
Malus domestica ‘Fuji’
Picea pungens ‘Procumbens'
What Are Some Ways That We Can Put Plants Into Groups?
Plants live in a variety of climates and niches
The adaptations that plants have made to survive in different climates allows for them to be classified into one of four major groups:– Bryophytes, Ferns, Gymnosperms and
Angiosperms
Bryophytes Belong to the phylum
Bryophyta Non-vascular plants
– No conducting tissues
Live in damp places Limited in size due to
lack of conducting tissue
Ex. Mosses and liverworts
Liverwort
Moss
Courtesy of Wm. C. Brown Publishers
Ferns Vascular plants Reproduce by
spores Have no true
leaves; 0nly fronds Fronds produce
food and spores New fronds called
fiddleheads
Ferns in the forest
Fiddleheads
Spores on underside of frond
Courtesy of Wm. C. Brown Publishers
Gymnosperms Reproduce with seeds
found in cones Also known as a conifer Leaves reduced to scales or
needles Most are evergreen – hold
on to their green color year round– Ex. Pines, spruce, cedar
Some can be deciduous- lose their leaves– Ex. Ginkgo, larch
Coniferous evergreen – Pinus contorta
Deciduous conifer –
Ginkgo biloba
Courtesy of Wm. C. Brown Publishers
Angiosperms
Plants that reproduce by flowers There are two types: monocotyledons
(monocots) & dicotyledons (dicots) A cotyledon is a food storage structure in
the seed. – Monocots have a single cotyledon
Ex. Grasses, corn and lilies
– Dicots have two cotyledons Ex. Roses, petunias and geraniums, beans
Angiosperms - Monocot Have flower parts
(sepals, petals, stamens,
pistils) in multiples of three– 3, 6, 9…
Parallel venation within the leaves
Stems with scattered vascular bundles
Narrow leaves Fibrous root system
Orchid – Paphiopedilum curtisii
Courtesy of Wm. C. Brown Publishers
Angiosperms - Dicot Flower parts are in
multiples of 4’s or 5’s– 4,12,16 or 5, 10, 15
Netted veins Vascular bundles
are in rings around the stem
Have broad leaves Taproot system
Hibiscus sp.
Courtesy of Wm. C. Brown Publishers
Monocot vs. Dicot
Courtesy of Wm. C. Brown Publishers
Monocot vs. Dicot
Why is distinguishing between monocots and dicots important in
landscape maintenance?
Stem Cross Section
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
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
Courtesy of Wm. C. Brown Publishers
Corn – Zea mays
See life cycle
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
Foxglove – Digitals purpurea
Courtesy of Wm. C. Brown PublishersSee life cycle
Perennials 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
Bristlecone pine – Pinus longaeva
See life cycle
Courtesy of Interstate Publishing
Germination----Growth---Flowering----Death
Germination---- Growth---Flowering----Dormancy
One or more flowering cycles
Germination---Growth---Dormancy---Growth---Flowering---Death
Season 1 Season 2
Back to Annuals
Back to Perennials
Back to Biennials
Summary What is the difference between an
angiosperm and a gymnosperm? How is a monocot different from a
dicot? Are evergreens herbaceous or woody
plants? How would you classify the grass
found outside on the lawn?
Summary Cont. What makes up the scientific name of a
plant? Why are scientific names written in Latin? In what group would you find mosses?
Describe their habitat. Describe the life cycle of a perennial. Name all 7 taxas in the classification
system.
Summary Cont. Can I spray Weed-b-gon on a lawn? Can I spray Grass-b-gon on day lilies? Could I spray Weed-b-gon on my
vegetable garden? What is the downside to including
biennials in a perennial flower garden? What are some practical classifications
I might want to give landscape plants?