Flowers, Inflorescences & Fruits
Flowers, Inflorescence & Fruits
• Floral characteristics are
the most commonly
features to identify
plants
• Much more reliable
than vegetative
characteristics
Flower
• A typical flower is a
stem tip bearing two
whorls of appendages
that are sterile and
two that are fertile
• All four whorls are
considered to be
modified leaves
Flower
• Typical flower
– 4 main parts
Flower
• Sterile parts
– Sepals: protect flower
bud
• All sepals called calyx
– Petals: pretty parts that
attract pollinators
• All petals called corolla
– Calyx and corolla make
up the perianth
Flower
• Fertile parts
– Stamens
• Male reproductive
structures
– Anther
– Filaments
– All stamens called
androecium
Flower
• Fertile parts
– Carpel
• Stigma
• Style
• Ovary
– All carpels called the
gynoecium
Presence or Absence of Parts
Terms Applied to Individual Flowers
• Complete: has all the
floral parts
–
–
–
–
Sepals
Petals
Stamens
Carpels
Presence or Absence of Parts
Terms Applied to Individual Flowers
• Incomplete: missing
one of more of the
floral parts
Ginger flower missing petals
Presence or Absence of Parts
Terms Applied to Individual Flowers
• Perfect (=bisexual):
flower with both
stamens and carpels
Grape flower with stamens and carpels
Presence or Absence of Parts
Terms Applied to Individual Flowers
• Imperfect (=unisexual):
missing stamens or
carpels, but not both
Presence or Absence of Parts
Terms Applied to Individual Flowers
• Staminate (=male):
unisexual flower with
just stamens present
Imperfect staminate flower; stamens only, no carples
Presence or Absence of Parts
Terms Applied to Individual Flowers
• Carpellate (=female):
unisexual flower just
carpels present
Imperfect carpellate flower; carpel only; no stamens
Presence or Absence of Parts
Terms Applied to Plants with Imperfect Flowers
• Monoecious: any plant
that has both staminate
and carpellate flowers
Presence or Absence of Parts
Terms Applied to Plants with Imperfect Flowers
• Dioecious: plant that
has either staminate
flowers or carpellate
flowers, but not both
Insertion of Floral Parts
• The position of the
gynoecium in
relation to all the
other floral parts is
the basis for for the
terminology used in
keys and taxonomic
descriptions
Insertion of Floral Parts
• Hypogynous: the sepals,
petals, and stamens are
inserted under the
carpel
– Ovary is said to be
superior
Insertion of Floral Parts
• In a perigynous flower,
the sepal, petals, and
stamens are fused
together to form a cup
called the hypanthium
– The gynoecium sits
inside the cup but is not
fused to it
– Ovary is said to be
superior
Insertion of Floral Parts
• In a epigynousflower,
the sepals, petals, and
stamens arise from a
point above the ovary
– Ovary is said to be
inferior
Floral Symmetry
• Actinomorphic (=radial):
cutting the flower in
any pane produces a
mirror image
Floral Symmetry
• Zygomorphic
(=bilateral): can cut the
flower in only one plane
to get a mirror image
Inflorescence Types
• An inflorescence is an
arrangement of one or
more flowers on a floral
axis
Inflorescence Types
• Inflorescence type
determined by:
– Number of flowers
– Positional relationships
– Degree of the
development of their
pedicels
– Nature of their
branching pattern
Simple Inflorescences
• Terminal: flower at the
tip of a stem
Scarlet rose-mallow (Hibiscus coccineus)
Compound Inflorescences
• Two or more flowers
per inflorescence
Compound Inflorescences
• Spike: elongate
inflorescence; flowers
are sessile, dense, or
remote from one
another
Spiked blazing star (Liatris spicata)
Compound Inflorescences
• Catkin: a pendant or
erect inflorescence in
which unisexual flowers
lack petals and are
hidden by scaly bracts
Compound Inflorescences
• Raceme: an elongate
inflorescence of
pedicellate flowers on
an unbranched rachis
Compound Inflorescences
• Umbel: a flat-topped or
somewhat rounded
inflorescence in which
all of the pedicels arise
from a common point
at the tip of the
peduncle
Butterfly weed (Asclepias sp.)
Compound Inflorescences
• Corymb: a flat-topped
or somewhat rounded
inflorescence in which
the pedicels of varying
length are inserted
along the rachis
Compound Inflorescences
• Panicle: a muchbranched inflorescence
with a central rachis
which bears branches
which are themselves
branched
Fruits
• Ripened or mature
ovary
• Contains seeds
Fruit Types
• Dry fruits
– Indehiscent
– Dehiscent
• Fleshy fruits
– True fruits
– False fruits
Fruit Types
Dry, Indehiscent
• Achene
Sunflower (Helianthus sp.)
Fruit Types
Dry, Indehiscent
• Caryopsis (=grain)
Fruit Types
Dry, Indehiscent
• Samara
Maple (Acer sp.)
Fruit Types
Dry, Indehiscent
• Schizocarp
Fruit Types
Dry, Dehiscent
• Capsule
Mexican buckeye (Ungnadia speciosa)
Fruit Types
Dry, Dehiscent
• Silique
Fruit Types
Dry, Dehiscent
• Legume
Fruit Types
Dry, Dehiscent
• Loment
Fruit Types
Dry, Dehiscent
• Follicle
Fleshy Fruits
True Fruits
• Derived from a
gynoecium of a single
flower
Fleshy Fruits
True Fruits
• Drupe
Fleshy Fruits
True Fruits
• Berry
Fleshy Fruits
True Fruits
• Pepo
Stink gourd (Cucurbita foetidissima)
Fleshy Fruits
True Fruits
• Pome
Fleshy Fruits
True Fruits
• Hesperidium
Fleshy Fruits
False Fruits
• Fruit derived from parts
other than the
gynoecium
Fleshy Fruits
False Fruits
• Accessory: fruit from
the receptacle
Fleshy Fruits
False Fruits
• Aggregate: fruit formed from many separate flowers
Magnolia (Magnolia sp.)
Fleshy Fruits
False Fruits
• Multiple: fruits formed
by the fusion of an
entire inflorescence
Fleshy Fruits
False Fruits
• Syconium: a hollow,
vase-like inflorescence
with the flowers lining
the inside
BREAK