Transcript Dicots

Chapter 24
Flowering Plants
and Civilization
Origin of Cultivated Plants

1880’s - Alphonse de Candolle, Origin of
Cultivated Plants
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
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Cultivated plants originated in areas where wild relatives
grow.
1916 - N. I. Vavilov
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Cultivated plants differ from wild relatives.
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Dispersal centers of cultivated plants are characterized by
presence of dominant genes.
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Recognized eight centers of diversity, with some plants
originating in more than one center
1950’s - Jack Harlan and students
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Associated crop origins with regions
Origin of Cultivated Plants
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Cultivated plants appear to have originated in
six major regions:
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Near-eastern region - Mediterranean, northern
Europe
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Chinese region - Temperate and southern China
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Barley, wheat, peas, lentils, asparagus, beets, carrots,
turnips, olives, cherries, plums, apricots, apples, onions,
garlic, broccoli, lettuce, flax, pistachios
Bamboo, peach, walnut, ginger, gourds, camphor, tea,
soybean, buckwheat, horseradish, cucumber
African continent - Mostly Ethiopia and West Africa
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Yams, sorghum, okra, sweet melons, coffee, some cotton
Origin of Cultivated Plants

Cultivated plants appear to have originated in
six major regions:
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South Asia and Pacific Islands
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North America
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Sugar cane, eggplant, mango, banana, citrus, safflower,
nutmeg, clove, cardamon, turmeric, black pepper,
coconut, taro, rice, sesame, onion
Sunflower, cranberry, blueberry, tobacco
South and Central America
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Garden beans, corn, peanut, white potato, lima beans,
cashew, pineapple, avocado, red pepper, tomato, cotton,
cocaine, cacao (chocolate), sweet potato, pumpkin,
squash, rubber, vanilla, cassava
Selected Families of Flowering Plants
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Dicots (now recognized in
two groups)
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The buttercup family
(Ranunculaceae)
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Nearly all 1,500 species are
herbaceous.
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Petals vary in number.
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Numerous stamens
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Several to many pistils with
superior ovaries
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Concentrated in north temperate and arctic regions
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Most at least slightly poisonous.
Buttercup
Dicots – The Buttercup Family
Columbine
Hepatica
• Five spurred petals
Monkshood or wolfsbane
• Yields aconite - Drug once used to treat rheumatism and neuralgia.
• Very poisonous
• Wolf hunters used juice from roots to poison wolves.
Dicots – The Laurel Family (Lauraceae)
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About 1,000 species of tropical evergreen shrubs and trees
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No petals, but sepals sometimes petal-like.
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Stamens in three or four whorls.
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Anthers open by flaps that lift up.
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Cinnamon - Pulverized
bark of small tree
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Cassia
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Camphor - Cold
remedies, insecticides
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Sassafras trees - Native
to eastern U.S.
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Sweet bay - Flavoring in
meat dishes
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Avocado
California bay
Dicots – The Poppy Family (Papaveraceae)
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Herbs of temperate and
subtropical regions
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Numerous stamens, but
single pistil
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Milky or colored sap
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All species produce
alkaloidal drugs.
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Opium poppies
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Opium - White fluid from
capsules
Morphine and codeine
– Heroin
Papaverine and noscapine
Poppy seeds
Prickly
poppy flower
Dicots – The Mustard Family (Brassicaceae)
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Nearly all 2,500 species in
temperate and cooler regions of
North America.
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Four flower petals arranged in a
cross.
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Six stamen: 2 short, 4 long
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Fruits = siliques or silicles
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All produce pungent watery juice.
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Many cultivated edible plants:
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Cauliflower, brussels sprouts,
broccoli, radish, turnip, horseradish,
watercress, rutabaga
Mustard - Ground seeds of two
species of Brassica
Shepherd’s purse
Dicots – The Rose Family (Rosaceae)
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More than 3,000 species of trees, shrubs and herbs
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Flowers have basal parts fused into cup, with petals,
sepals and numerous stamens attached to cup’s rim.
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Family subdivided into subfamilies on basis of flower
structure and fruits.
Dicots – The Rose Family (Rosaceae)
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Enormous economic impact:
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Stone fruits: cherries, apricots, peaches, plums
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Pome fruits: apples, pears
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Aggregate fruits: strawberries, blackberries, raspberries
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Garden ornamentals - Roses
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Fragrances
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Fruits of roses = hips - Vitamin C
Raspberry
Rose hips
Dicots – The Legume Family (Fabaceae)
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Third largest of flowering plant families with 13,000
species
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Cosmopolitan
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Flowers radial to bilateral.
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Stamens fused into tube around ovary.
Bilateral flower
showing stamen
tube
Inflorescence of radial flowers
Dicots – The Legume Family (Fabaceae)
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Fruit is a legume.
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Many important crop
plants:
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Peas
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Beans
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Soybeans
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Peanuts
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Alfalfa
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Sweet clover
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Licorice
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Carob
Winged bean
Dicots – The Spurge Family (Euphorbiaceae)
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In tropical and temperate regions
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Several economically important plants
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Cassava - Staple food in tropical regions
Para rubber tree - Crude rubber from latex of inner bark
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Stamens and pistils produced in separate flowers.
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Flowers often inconspicuous and lack corolla.
Poinsettia
Dicots – The Spurge Family (Euphorbiaceae)
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Inflorescence = cyathium
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Female flower elevated on stalk called gynophore and surrounded by
several male flowers that each consist of little more than an anther.
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Male and female flowers inserted on a cup composed of fused bracts,
usually with glands on rim.
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Sometimes surrounded by colored bracts (poinsettia)
Dicots – The Cactus Family (Cactaceae)
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More than 1,500
species native
only to Americas
in dry,
subtropical
regions.
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Leaves reduced
in size, often
spines.
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Fleshy stems
Dicots – The Cactus Family (Cactaceae)
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Flowers showy.
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Numerous stamens,
petals and sepals
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Inferior ovary
develops into berry.
Most have edible
fruit.
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Prickly pear fruits
Dicots – The Mint Family (Lamiaceae)
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3,000 species
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Unique combination
of angular stems that
are square in cross
section, opposite
leaves, and bilaterally
symmetrical flowers
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Ovary superior and
four-parted,
developing into four
nutlets.
Lamb’s ear mint
Dicots – The Mint Family (Lamiaceae)
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Plants produce mint oils
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Used medicinally and as
antiseptic in different parts
of the world.
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Menthol used in
toothpaste, candies, gum,
liqueurs, and cigarettes.
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Rosemary, thyme, sage,
oregano, marjoram, basil,
lavender, catnip,
peppermint, spearmint
Peppermint
Dicots – The Nightshade Family (Solanaceae)
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3,000 species concentrated in tropics of Central and
South America.
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Flowers have fused petals with stamens fused to corolla.
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Superior ovary develops into berry or capsule.
Dicots – The Nightshade Family (Solanaceae)
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Tomato, white potato, eggplant, peppers, tobacco, petunia
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Many nightshades poisonous and some have drug uses.
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Belladonna drug
complex:
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Atropine - Shock
treatment, pain
relief
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Scopolamine Tranquilizer
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Capsicum from red
pepper - Gastric
stimulant
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Jimson weed Asthma
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Tobacco
Tomato harvester
Dicots – The Carrot Family (Apiaceae)
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Approximately 2,000 members widely distributed in
Northern Hemisphere.
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Savory-aromatic herbs, with dissected leaves, and petiole
bases that form sheaths around stem
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Flowers small, numerous and
arranged in umbels.
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Inferior ovary and two-lobed
stigma
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Dill, celery, carrot, parsley,
caraway, coriander, fennel,
anise, parsnip
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Some members poisonous.
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Water hemlock - Socrates believed
to have died from ingestion.
Water hemlock
Dicots – The Pumpkin Family (Cucurbitaceae)
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700 species of
prostrate or climbing
herbaceous vines
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Flowers unisexual with
fused petals.
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Male
flower
Female flowers with
inferior ovary of three
carpels
Female flower with inferior ovary
Dicots – The Pumpkin Family (Cucurbitaceae)
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Includes many
important edible plants
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Many have been
cultivated for so long
they are unknown in a
wild state.
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Pumpkins, squashes,
cucumbers,
cantaloupes, gourds
Dicots – The Sunflower Family (Asteraceae)
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Second largest flowering plant family with
about 20,000 species
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Dandelions, lettuce, endive, chicory,
artichoke, dahlia, chrysanthemum, marigold,
sunflower, thistle
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Tarragon - Spice in meat and pickle
Dicots – The Sunflower Family (Asteraceae)
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Individual
flowers =
florets
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Florets
arranged in
compact
inflorescence
that
resembles a
single flower.
Selected Families of Flowering Plants
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Monocots - The grass family (Poaceae)
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Flowers windpollinated and
highly specialized.
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Calyx and corolla
are tiny scales.
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Flowers protected
in boat-shaped
bracts.
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Stigmas exposed
and feathery.
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Leaf bases sheath
stems.
Monocots – The Grass Family (Poaceae)
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Contains nearly all cereals
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Wheat, barley, rye, oats, rice,
corn
Sugar cane - Six meters tall
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Juice squeezed from cane,
then centrifuged.
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Solids crystallized into table
sugar.
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Dark remnant = molasses
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Baskets, fibers, thatching
for huts
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Citronella
Sugar cane
Monocots – The Lily Family (Liliaceae)
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Approximately 4,550
members that occur
in almost any area
supporting
vegetation
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Flowers often large
and their parts are in
multiples of three,
with sepals and
petals often
resembling each
other.
Monocots – The Lily Family (Liliaceae)
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Lilies, daffodils,
asparagus, sarsaparilla,
Aloe, onions, garlic
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Meadow saffron Source of colchicine
used to treat
rheumatism
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Bowstring hemps
(sansevierias) - House
plants; long fibers for
string, rope, bowstrings
Sansevieria
Monocots – The Orchid Family (Orchidaceae)
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Very large family with > 35,000 species,
especially abundant in tropics
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Widely distributed with diverse habitats
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Flowers exceptionally varied in size and form.
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Many epiphytic on bark of trees.
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Others aquatic or terrestrial and saprophytic.
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Specific adaptations between orchid flowers and
pollinators are extraordinary and sometimes
bizarre.
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Vanilla from vanilla orchid.
Monocots – The Orchid Family (Orchidaceae)
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Three sepals and petals,
with one of petals (lip petal)
differing from other two
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Stamens and pistil united in
single structure = column.
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Anthers contain sacs of
pollen called pollinia.
Minute seeds produced in
prodigious numbers.
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Each seed consists of only a
few cells.
Seed must become
associated with specific
mycorrhizal fungus to
germinate.
Review

Origin of Cultivated Plants

Selected Families of Flowering Plants
Dicots
Monocots
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The Buttercup Family (Ranunculaceae)
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The Grass Family (Poaceae)
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The Laurel Family (Lauraceae)
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The Lily Family (Liliaceae)
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The Poppy Family (Papaveraceae)
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The Orchid Family (Orchidaceae)
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The Mustard Family (Brassicaceae)
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The Rose Family (Rosaceae)
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The Legume Family (Fabaceae)
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The Spurge Family (Euphorbiaceae)
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The Cactus Family (Cactaceae)
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The Mint Family (Lamiaceae)
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The Nightshade Family (Solanaceae)
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The Carrot Family (Apiaceae)
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The Pumpkin Family (Cucurbitaceae)
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The Sunflower Family (Asteraceae)