Transcript Begin Basic Botany Unit

Botany = Plant Science
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Agronomy - field crops, wheat, corn,
soybeans
Horticulture - fruits, veggies, woody
ornamentals and floriculture crops
Forestry - wood and pulp production,
recreation, wildlife and watershed
management
Weed science - deal with controlling and
management of unwanted plants.
Major Uses of Plants as FOOD
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Grains – wheat, corn, oats, rye, barley, millet and grain
sorghum
Starchy Foods – potatoes, sweet potato, cassava, yam,
banana
Vegetables - sweet corn, snap bea, pea, bean, lettuce
Fruits – apples, strawberries, blueberries, raspberries,
watermelon
Sugar Crops – sugar beets, sugar cane, (corn syrup)
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Oil Crops – soybean, sunflower, peanut, corn,
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cottonseed, olive
Nuts - Walnut, Pecan; Spices – Vanilla, Pepper, Allspice, Oregano;
Beverages – Coffee, Chocolate, Tea
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Nonfood Uses of Plants
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Fiber Crops
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Cotton and Flax
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Natural fibers have been replaced with synthetics.
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Common to see a blend of natural and synthetic fibers
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Nylon, rayon, polyester
Cotton/polyester blend
Timber, Fuel and Pulp
Aesthetic Uses
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Cut flowers, turf grasses, green foliage
Other Plant Products
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Medicines
Drugs
Perfumes
Cosmetics
Insecticides
Industrial chemicals
Careers in Plant Science (with a high school diploma)
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Greenhouse caretaker
Plant propagator
Orchard Care Taker
Pesticide Applicator
Groundskeeper
Tractor Operator
Combine harvester
Careers in Plant Science with
a 2-year (associate's) degree
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Greenhouse manager
Golf course manager
Pesticide dealer
Crop supply salesperson
Greenhouse supply
salesperson
4-year degree job
opportunities in Plant Science
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Crop marketing specialist
Crop production specialist
Fertilizer technologist
Erosion control scientist
Soil conservationist
Seed technologist
Turf grass specialist
Graduate level careers in
Plant Science
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Plant geneticist
Plant breeder
Biotechnologist
Genetic engineer
Plant pathologist
Plant physiologist
Statistician
Weed scientist
Basic Botany
Roots
Stems
Leaves
Flowers
Seeds
Plant Classifications
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Angiosperm: produces seeds enclosed in a fruit
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1. Monocot: one seed leaf (cotyledon)
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ex. Corn, grass
2. Dicot: two seed leaves
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Ex: corn, deciduous trees
ex. Beans, trees
Gymnosperms: produces seeds enclosed in cones
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Ex: evergreen and pine trees
Root Functions
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Absorption of water and nutrients
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(root hairs take up oxygen and water and
it is transported through the xylem tissue
in the plant)
Transportation of water and nutrients to
stem
Anchor plant to maintain stability
Stores food and water
Root System
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Primary root: short-lived, develops
from embryo
Secondary root: branches from
primary root, fibrous root, becomes
primary root
Root hairs: extensions reach between
soil particles; absorbs water and
nutrients; needs care when
transplanting
Parts of Roots
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Root hairs - site of absorption, one-celled,
white, fuzzy hair-like growths that develop
near the end of the root branches
Root tip - where the root grows in length (4 to
6 cm of the “free end”)
Root cap - provides protection for the root tip
Epidermis - the outermost layer of cells
Cortex: - undifferentiated plant tissue from
which new cells arise at the tips of roots
(under root cap)
Root Hairs on a Tomato Plant
Parts of Roots
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Growing point - just back of the root cap
where active cell division
Vascular tissue - is within the cortex,
contains cells which transport water,
nutrients, and minerals to all parts of the
plant.
Elongation region - where rapid growth in the
length of the root takes place.
Region of maturation - lies behind the
growing point and is where secondary roots
Types of Root Systems
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1. Taproots: primary roots; reach deep
into soil
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2. Fibrous: no real primary roots;
many fine roots, spread out at soil
surface
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ex. Carrot, dandelions, oak
ex. Annuals, grasses, shrubs
3. Fleshy: become food reservoirs,
store surplus food
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ex. Carrots, turnips, beets
Basic Plant Parts
STEMS
Function of Stems
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Attachment
point for leaves,
flowers, fruit
Support
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Leaves have to
have access to
light and air
Function of Stems
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Transport
FOOD, WATER,
MINERALS
 Through Capillary Action
 Vascular System:
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Xylem = water and nutrients taken
from roots to leaves
 Phloem = manufactured food
distributed to all parts of the plants
 Storage = of water, nutrients, waste
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Vascular Systems
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Monocot: bundles scattered
throughout stem
Dicots: segregated into circular
pattern; separated by cambium layer
(produces new xylem & phloem cells)
Monocot Stem
EPIDERMIS
BUNDLE CAP
XYLEM
PHLOEM
Vascular bundles in a scattered arrangement
Monocot Stem
Dicot Stem
Epidermis
Bundle Cap
Xylem
Cambium Layer
Phloem
Vascular bundles in a circular arrangement
Dicot Stem
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Woody = accumulated dead xylem
cells
Herbaceous = nonwoody - succulent
(corn, weeds, beans, annual flowers)
Stem Structure:
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Terminal bud = tip of stem, point of
elongation (cut it off and it’ll get a bushy
plant)
Auxillary bud = located above each leaf
Node = where the leaf is attached
Internode = region between nodes
Stem Growth
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Growth in LENGTH = meristematic cells =
active cell division
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Apical meristems = tips
Growth in DIAMETER = cambium layer
(rings)
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Cells divide between xylem and phloem
Stem grows in diameter when:
cambium layer divides on inner side of stem =
new xylem and on outer side of stem = new
phloem
Trees in dormant seasons add different colors to
the growth layers = rings
Basic Plant Parts
LEAVES
Function
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To absorb sunlight for the
manufacturing of plant sugars
Photosynthesis
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Flattened surfaces present a large area for
absorption of light energy
To make food used by plants for growth
& reproduction
Types of Leaves
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Scale leaves - small, leathery,
protective leaves, enclose & protect
buds
Seed leaves - cotyledons, are modified
leaves (storage organs).
Spines and tendrils - modified leaves
that protect or assist in supporting
stems
Types of Leaves
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Storage leaves - found in bulbs and
succulents, serve as food storage
Bracts - which are often brightly
colored (poinsettia)
Conifers,(pines, firs, spruce)needleswaxy cuticles with sunken stomata
 resin canals on sides of vascular system
to guard against insect damage
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Dicot Parts of a Leaf
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Blade - broad, thin part of leaf
Petiole - thin stem attaching leaf to stem
Sessile - leaves with no petiole
Midrib - large, central vein
Margin - edge of leaf
Secondary vein - branches from main vein
Apex or tip - top of leaf
Base - bottom of leaf
Monocots
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Sheath - portion of leaf
blade surrounding stem
Ligule - “collar”
extension of sheath
curving around stem
Auricles - appendages
that surround stem at
junction of blade and
sheath
Cross-Section of A Leaf
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Epidermis - protection of leaf tissue
Cuticle - waxy substance (cutin) protects leaf from
dehydration
Guard cells - open and close, regulate passage of
H2O, O2, and CO2
Stoma - openings in leaf surface
Mesophyll - middle layer of leaf, where
photosynthesis occurs
 Palisade layer - dense upper layer
 Spongy mesophyll - lower layer air space
Chloroplasts - actual sites of photosynthesis
Leaf Characteristics
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Simple - one blade
per leaf
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ex: grass, oak, apple
Compound - several
leaflets
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ex: sumac, locust
2 Types:
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Palmate
Pinnate
Leaf Arrangement along a
Stem
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Rosulate - basal leaves form a rosette
around stem
Alternate - leaves occur at alternate spots
on stem; single leaf at each node
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Opposite - leaves occur two at a node on
opposite sides of stem
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oak, beech
maple, ash, dogwood
Whorled - 3 or more leaves at each node
Looks compound but
is actually simple
Venation - arrangement of
veins
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Parallel - from base to tip in parallel lines
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ex. Grasses/monocots
Net-veined - veins branch from main
midrib(s) and subdivide to finer veinlets
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more resistant to tearing
Pinnate - veins are lateral from midrib to edge
Palmate venation - principal vein extends
outward, like ribs of a fan
ex. Dicots, apple, maple leaves
Tomatoes - Spiral Leaf
Arrangement
Unpruned
vs.
Pruned
Flowers
Basic Plant Parts
Purpose of Flowers
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POLLINATION = Plant Sexual
Reproduction
Brightly colored & fragrant to attract bees,
insects, birds
 Pollination occurs by animals, wind,
human activity
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Flowers
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Dicots - typically have four or five
sepals and/or petals, or multiples
thereof
Monocots - typically come in threes or
multiples of three
Flowers Contain 4 Parts
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Sepals: small, green, leaflike
structures located at the base of a
flower - protects opening bud and
flower; supports petals; also called a
calyx
Petals: highly colored portions of a
flower to attract pollination
Stamen: male part of the flower
Pistil: female part of the flower
Female Part of the Flower
(PISTIL)
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Stigma: pollen-collecting
structure at top of pistil
Style: support structure
connecting ovary and
stigma
Ovary: enlarged base of
the pistil contains ovules
(eggs), if an egg is
fertilized, the ovule
develops into a seed.
Pollination: pollen is
collected at stigma, travels
down style and reaches
the ovary
Male parts of the flower
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Stamen:
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Anther: pollen sac - located
at top of structure...Contains
pollen
Filament: stalk supporting
anther, holds the anther in
position, making the pollen
available for dispersement
by wind, insects, or birds
Tomato Flower
Types of Flowers
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Complete/Perfect: flower with all four
parts
Incomplete/Imperfect: flower missing
any of the four parts
Corn plant: male and female parts in
different places on one plant
Male part = tassel
 Female part = ears
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Incomplete Flower
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Has ONLY male parts or female parts
Male flower – sepals, petals & stamens but
no pistil
Female flower – sepals, petals, & pistil, but
no stamens
Examples: Kiwi, Ginkgo
Plants are classified by
reproduction life spans
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Annual: completes life cycle in one year
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Biennial: 2 year life cycle. Grows vegetation
in one year. Flowers and dies off second
year
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Ex: bedding plants, vegetables, corn, wheat
Ex. Celery, asparagus, wild carrot
Perennial: life span of 2 + years
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Ex. Trees, shrubs
Tomato Reproductive Cycle
Developing Buds
Fertilized Flower
Immature Flowers
Mature Flower
Immature Fruit
Mature Fruit
Developing Fruit
SEXUAL & ASEXUAL
REPRODUCTION
Sexual & Asexual
Reproduction
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Sexual: Propagation is by seed
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Asexual: Propagation is the increase
of plants by vegetative methods.
Sexual Reproduction
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Advantages
more economical
 easier
 longer storage time
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Disadvantages
do not breed true
 slow growth
 do not produce viable seeds
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How do pollen grains fertilize
the ovules?
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Pollen grains are carried by wind,
water, or animals
Pollen lands on stigma, pollen tubes
move toward ovary
Fertilization happens in ovary
Embryo is formed
Embryo grows outward and forms fruit
or seed
Sexual Reproduction
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Self-fertilization, pollen and ovules are made by the
same plant.
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Cross-fertilization, pollen and ovules come from
genetically different plants.
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Cross-fertilization often leads to vigorous, highly productive
plants, an effect called hybrid vigor.
Cross-pollination is useful in plant breeding
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Repeated self-fertilization results in inbreeding. Inbred plants
often show reduced vigor and make fewer fruits and seeds.
Can be done by removing anthers from a plant before
pollination, so that the grower can supply pollen from another
selected plant
Some plants cannot self-pollinate.
Some plants have distinct male and female individuals.
Asexual Reproduction
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Vegetative reproduction is asexual
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Three types of cuttings:
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a= without
Tip cutting
Leaf section, leaf petiole, or cutting veins
Cutting of roots
Ensure new plants are identical to parent
plants
Maintain desirable species
Common types of
asexual propagation
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Cuttings - portion of plant removed and forms roots
(shrubs/houseplants)
Grafting - shoot removed from parent plant and placed
on another (apple/fruit trees)
Budding - bud removed from parent plant and placed on
stock (fruit trees/ornamentals roses)
Division - clumps of plants dug up and separated
(hostas, mums, lilies)
Rhizomes - rhizomes dug up, cut into sections and
planted (iris)
Stolon - new plants root at nodes (strawberries
SEEDS
Sexual Reproduction
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Requires flowers to form, pollination &
fertilization to occur, seeds develop and
grow
Pollen from anther falls on stigma of
pistil from anther of stamen
Fertilization occurs in ovary
Ovary develops into fruit and ovules
become seed
Seeds are living or dormant
3 parts:
1.
2.
3.
seed coat
endosperm/cotyledon
embryo
Parts of the Seed
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Seed Coat
Protective outer covering of the seed
 Helps transport seeds and keep them
viable (alive)
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Endosperm
Stores plant food (starch & protein)
 Feeds the growing embryo during
germination
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Parts of the Seed
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Cotyledon
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Seed leaf - first leaves seen on a plant. Feeds
the plant during first growth
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Dicots = 2
Monocots = 1
Embryo
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New plant that develops as a result of fertilization
Epicotyl - forms all plant parts above the first
node of the stem.
Hypocotyl - forms the lower stem and roots
Seeds
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Angiosperm— flowering plants, seeds
are born in an enclosed ovary
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(some 250,000 species)
Gymnosperm— seeds of
gymnosperms are born naked with no
ovary (pines, spruces, and ginkgo 700
species)
Germination
1.
2.
3.
4.
5.
Seed coat softened by water
Favorable temperatures must exist
Endosperm feeds growing plant
Epicotyl - grows away from gravity
Hypocotyl - grows toward gravitational
attraction
Monocots vs. Dicots
Cotyledons
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Monocots (grasses); remains
inside seed for a
longer period
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Dicots - push up
through the soil at
germination and act
as true leaves
Monocot Growth
Dicot Growth
FRUIT
Fruit Consists of:
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Fertilized and mature ovules = SEEDS
Ovary wall
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Seeds enclosed within the ovary
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Fleshy, as in the apple, or dry and hard as
in a maple fruit
apples, peaches, oranges, squash,
cucumbers
Seeds situated on outside of fruit tissue
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corn, strawberry
Types of Fruit - Simple
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Develop from a single ovary
Cherries and peaches (drupe), pears and
apples (pome), and tomatoes (berries)
 Tomatoes are a botanical fruit since they
develop from the flower, as do squash,
cucumbers, and eggplant
 DRY: (fruit wall becomes papery and hard)
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Peanut (legumes), poppy (capsule), maple
(samara), and walnut (nut)
Tomato
Types of Fruit - Aggregate
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Come from a single
flower which has
many ovaries
Ovaries are
fertilized separately
and independently
Strawberry and
blackberry have an
edible, enlarged
receptacle
Types of Fruit - Multiple
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Tight cluster of
separate,
independent flowers
on a single structure
Each flower will
have its own calyx
and corolla
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Pineapple, fig and
the beet seed