Flower Morphology
Basic Floral Structure
• Essential/ reproductive structures
- concerned with sporogenesis and gametogenesis
- pistil/ carpel/ gynoecium and stamen/androecium
• Accessory/ sterile structures
- does not participate in spore/ sex cell formation
- perianth, receptacle
Presence/ absence of floral parts
(corolla, calyx, stamen, pistil)
Complete flower VS Incomplete flower
Presence/ absence of essential
reproductive structures
• Perfect/ Bisexual flower VS Imperfect flower
Symmetry
• Actinomorphic/ Regular flower VS
Zygomorphic flower
Petal Attachment
• Apopetalous/ Polypetalous flower VS
Gamopetalous flower VS Apetalous flower
Corolla tube
Ovary position
• Superior/ hypogynous flower VS Inferior/
epigynous flower VS Semi- inferior/
perigynous flower
FLOWERS: Placentation.
•
1.
2.
3.
4.
5.
Pattern of ovule attachment and
distribution in an ovary.
Axile - ovules are borne on
placentae on the central axis of a
compound ovary.
Basal - has a single ovule that is
almost at the base of the ovary.
Marginal - ovules are borne along
the fused margins of placenta of a
single ovary.
Parietal - ovules are borne in
placentae located on the inner
surface of the outer wall of the
ovary.
Free central - ovules are borne on
placentae on a free, central column
within an ovary that has only one
locule.
FLOWERS: Composites.
• A single flower with
many tiny separate
flowers densely
clustered together on a
common receptacle.
• Example: Asteraceae
family.
1. Sunflowers
2. Daisies
3. Chrysanthemums
FLOWERS: Composites.
• Inflorescence: head or capitate.
• 2 kinds of flowers in the head:
1. Ray flowers: corolla looks like one
petal.
• found on the outer edge of the head
2. Disk flowers: corolla forms a tube of
united or fused petals.
• Constitutes the inner circle.
• In some composites, the disk
flowers are missing and the head
consists only of ray flowers.
• In others, it is the ray flowers that
are missing and the head consists
only of disk flowers.
FLOWERS: Grasses.
• Grasses: flowers, highly modified.
• The individual grass flower, the
floret is enveloped by a pair of
bracts or modified leaves.
• The outer and larger bract is
termed the lemma and the inner
and smaller one is called the
palea.
• The palea encloses the stamens
and the pistil.
• When the flower is mature, the
stamens are large and usually
extend well above the stigma.
• The stigma is feathery and large
Cross Pollination VS Self Pollination
(Advantage and Disadvantage?)
Microsporogenesis &
Microgametogenesis
Anther Cross Section
Anther Cross Section
Epidermis
Vascular strand
Endothecium
Stomium
Pollen
grain/s
Anther Cross Section
Pollen sac
Tapetum layer
Anther Cross Section
• Tapetum layer
parenchyma cells that
surrounds the Pollen sac
• Epidermis
Outer layer of anther
• Endothecium
Parenchyma cells that
constitutes the rest of the
anther
Pollen grain
Intine – inner layer of the pollen grain
Exine – outer layer
Tube Nucleus – give rise to the Pollen tube
Generative Nucleus – for fertilization
Pollen Grain with Pollen TUBE
X-S ovule
Ovule
(3)
(2)
(2)
(to be FERTILIZED)
Fertilization
Ovules becomes the SEED
Seed (Dicot)
Plumule
Epicotyl
Seed coat/testa
Hypocotyl
Radicle
Cotlyedon
Seed (Monocot)
Monocot VS Dicot growth pattern
HYPOGEAL
EPIGEAL
Seed germination
1.Absorption of water in the micropyle.
2. Increased metabolic rates
3. Cellular respiration proceeds
4. Cell division and growth proceeds.
5. Rupture of the seed coat
6. Embryo sprouting
disperse their seed without any help from
an external vector
a vector or secondary agent is used to
disperse seeds
Ovary to Fruit (Matured, Ripened
Ovaries)
Infloresence
Spadix infloresence
Raceme
Spike
Corymb
Head
Panicle
Umbel
Cyme
Fruits
According to Flower Origin
Multiple
Simple
Aggregate
Nature of Pericarp
Fleshy
Dry
Nature of Dispersal
Berry
Hesperidium
Pepo
Drupe
Pome
Dehiscent
Indehiscent
Legume
Follicle
Capsule
Silique
Achene
Grain
Samara
Nut
Multiple Fruit
Pineapple (Ananas comosus)
formed from an inflorescence.
Each flower in the inflorescence produces
a fruit, but these mature into a single mass in
which each flower has produced a true fruit
Jackfruit
(Artocarpus heterophyllus)
fruit that develops from the merger of several
ovaries that were separate in a single flower.
Aggregate Fruit
Raspberry (Rubus strigosus)
sugar-apple, or sweetsop
(Annona squamosa)
Blackberry (Rubus fruticosus)
Fruits
According to Flower Origin
Multiple
Simple
Aggregate
Nature of Pericarp
Fleshy
Dry
Nature of Dispersal
Berry
Hesperidium
Pepo
Drupe
Pome
Dehiscent
Indehiscent
Legume
Follicle
Capsule
Silique
Achene
Grain
Samara
Nut
Fruit- Berry
A fleshy fruit without a stone produced from a
single flower containing one ovary
Banana (Musa acuminata)
Pepper (Capsicum annuum)
Tomato (Solanum lycopersicum)
Hesperidium
A fleshy fruit with tough, leathery, aromatic rind.
Orange (Citrus sinensis)
Calamondin (Citrus microcarpa)
Pepo
hard, thick rind;
typical fruit of the gourd family
(Cucurbitaceae)
Watermelon
(Citrullus lanatus_
cucumber (Cucumis sativus)
Drupe
one-seeded fruit with the pericarp distinctly
divided into thin skin-like exocarp, thick fleshy
mesocarp and hard, stony endocarp
coconut (Cocos nucifera)
Coffee (Coffea arabica)
Mango (Mangifera indica)
Pome
fruit with papery pericarp
Pear (Pyrus amydaliformes)
apple (Malus domestica)
Fruits
According to Flower Origin
Multiple
Simple
Aggregate
Nature of Pericarp
Fleshy
Dry
Nature of Dispersal
Berry
Hesperidium
Pepo
Drupe
Pome
Dehiscent
Indehiscent
Legume
Follicle
Capsule
Silique
Achene
Grain
Samara
Nut
Legume/ Pod
splits along two seams
peanut(Arachis hypogaea)
Tamarind (Tamarindus indica)
splits in a variety of ways
Capsule
Lady finger’s (Abelmoschus esculentus)
Cotton (Gossypium hirsutum)
Follicle
splits along one seam
Milkweed (Asclepias syriaca)
Silique
two fused carpels that separate, leaving a
persistent wall between them
Mustard (Brassica campestris)
Fruits
According to Flower Origin
Multiple
Simple
Aggregate
Nature of Pericarp
Fleshy
Dry
Nature of Dispersal
Berry
Hesperidium
Pepo
Drupe
Pome
Dehiscent
Indehiscent
Legume
Follicle
Capsule
Silique
Achene
Grain
Samara
Nut
Grain
one seeded the coat of which is
completely fused to the inner
surface of the pericarp
Rice (Oryza sativa)
Achene
one seed can be separated from
the ovary wall except at point of
attachment to the inside of the
pericarp
Nut
one seeded fruit similar to achene but with a
very hard and thick pericarp
Walnut (Juglans regia)
Chestnut (Castanea dentata)
Oak (Quercus alba)
Samara
an achene-like fruit with wing-like outgrowth
Narra (Pterocarpus inducus)
Free Central
- ovules are attached to a central axis of a uniloculate ovary
Axile
- ovules are attached to a central axis in a multiloculate ovary
Parietal
- ovules are found along the walls of a uniloculate ovary
Basal
Marginal