Ornamental Plants - Socio Economic Impact of Plants - Lecture Slides, Slides for Sociology. Avinashilingam University


Description: These are the lecture slides of Socio Economic Impact of Plants. Key important points are: Ornamental Plants, Naming Ornamentals, Cultivar Names, Types of Ornamentals, Asteraceae Ornamental Family, Variations on Theme, Inspiration for Big Orange, Polyploidy Breeding Tool
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Tuesday Lecture – Ornamental Plants

Ornamental Plants


Quiz 1. Describe a factor that could result in a plant having a

leaf that has a coloration other than solid green.

2. Describe a feature of the UTIA Gardens that you particularly liked.


Naming Ornamentals Difficulties introduced by the nature of ornamentals:

- often hybrids

- many are sterile, propagated vegetatively

- mutants with striking features – propagated vegetatively to retain features

- marketing

International Code of Horticultural Nomenclature – sets of rules governing assignment of cultivar names

 Some widely grown plants may have a registry of cultivar names


Cultivar Names 2. Variation within cultivated plants

- “variety” – widely (and still) used

- cultivar (cultivated variety)

Used to denote an assemblage of cultivated plants that is clearly distinguished by some character(s) and that following reproduction retains its distinguishing character(s)

Cultivar name is written in any language except for Latin

Cultivar name can be combined with a generic, specific, or common name:

Citrullus cv. Crimson Sweet;

watermelon cv. Crimson Sweet;

Citrullus lanatus cv. Crimson Sweet Docsity.com

Types of Ornamentals

1. Nursery Crops – planted outside

- trees/shrubs; turf; ground covers; bedding plants

2. Florist Crops – grown for cut flowers or foliage

- increased worldwide: $12.5 billion (1985)  $25 billion (2009)

3. Houseplants – sold for growing indoors

- plants must survive in harsh environment


Asteraceae – The Ornamental Family - Ageratum

- Aster

- Black-eyed Susan

- Cornflower

- Dahlia

- Daisy

- Marigold

- Chrysanthemum (Dendranthemum)

- Sunflower

- Zinnia Docsity.com

Variations on a Theme Dandelion – all rays Cornflower – All

Disk/outer ones larger Pussytoes – all disk


Another Double

Single Marigold Double Marigold

Marigold – Tagetes - native to Mexico


Daisy – Inspiration for “Big Orange”

Shasta Daisy – tetraploid selection of Luther Burbank

UT Uniform Color – traces origin to center of daisy heads


Polyploidy – Breeding Tool

Daylilies – Hemerocallis fulva

Diploid Tetraploid

Polyploidy: >2 sets of chromosomes

1. Determinate organs will be larger

2. Stabilizes (and sometimes makes fertile) hybrids

3. Odd polyploids  often sterile:

- no messy seeds

- no need to “deadhead”


More Flower Variations “doubled” flowers – stamen primordia  petals

Pink Carnation


Araceae – the Houseplant Family Many Aroids – tropical epiphytes – habitat similar to house/apartment


Spathiphyllum – the Mall Plant Note: inflorescence is spathe + spadix


Amorphophallus – a Giant Aroid 1.37 m tall


Amorphophallus titanum

Geneticist Huge de Vries, one of the rediscoverers of Mendel’s Laws, provides scale for an inflorescence of the “Voodoo Plant”


How Dumb Cane Got Its Name Calcium oxalate – characteristic crystalline inclusions (raphides) in Araceae  extreme irritation of mucous membranes

Can lead to fatal swelling of passages to lungs


Commonly Ingested Aroids

From List of “Top 20 Ingested Plants” Reported to Poison Control Centers in U.S.:

2. Philodendron

4. Spathiphyllum

6. Dieffenbachia

10. Epipremnum (Pothos)

Treatment: Symptomatic and Supportive – remove residue from mouth; provide liquids; monitor breathing (major danger is suffocation is swelling is severe)


Invasive Plants – The Dark Side of Ornamentals

Invasive Plants = “Biological Pollution”

“Rule of 10’s”:

For every 10 plants introduced, 1 will become established

For every 10 established, 1 will become invasive

1 in 100 introductions becomes invasive

Often a long lag time, introduction  problematic invader

How to Predict Invasiveness?

- only clear guide, if invasive in other areas


Dandelion - Invader Taraxacum officinale (“of the shops”)

Dandelion (“dents du lion” = lion’s tooth, from leaves)

Asteraceae – all ray flowers

Introduced by Pilgrims – used as spring potherb

Flowers – produce abundant nectar  sugar source to produce wine

Apomictic – seeds produced without fertilization  clones of parent

Will mature its seed even if uprooted Docsity.com

Tennessee Invaders

TN-EPPC (Tennessee Exotic Pest Plant Council) – List

Trees: Mimosa (Albizzia); Princess Tree (Paulownia); Tree-of- Heaven (Ailanthus)

Shrubs: Autumn Olive (Eleagnus); Bush Honeysuckles (Lonicera); Japanese Barberry (Berberis); Multiflora Rose (Rosa); Privet (Ligustrum)

Herbs: Purple loosestrife (Lythrum); others

Vines: Euonymus; Japanese honeysuckle (Lonicera); Japanese wisteria; Kudzu (Peuraria); Oriental Bittersweet (Celastrus)


Native Plants – A Great Resource

Answer to Invaders = use native plants

See Box 17.2, p. 429 Wildscaping

Opportunity: provide plants for revegetation, environmental restoration projects


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