Download Introduction to Flowers - Millennium Organization

Introduction to Flowers
 Definition: a compressed, modified fertile shoot carrying modified leaves, highly specialized
for the reproductive function and adapted to produce fruits and seeds.
(Hena el leaves 3andaha different function gheer el 3ade bet3aha el howa metabolism w
photosynthesis .. el leaves bet-adapt 3ashan teb2a used for reproduction)
 A Typical Flower is usually formed of:
Flower-stalk or Pedicel
The axis that four sets of floral leaves are
arranged on.
Receptacle (Hypanthium)
The swollen or expanded apex.
3ashan el flower tetzebet feh hetta min el apex
betb2a modakhama bensameha el Receptacle
Floral leaves
Sexual [Essential]
Asexual [Non-essential]
Calyx
Corolla
Composed of carpels
Gynoecium
(Pistil, Female Organ)
Androecium (Male Organ)
Composed of stamens
composed
of sepals

composed
of petals
Anther
Filament
Ovary
Accessory (sa3at mawgooda w sa3at la2) leafy structure:
Bract
Style
Stigma
definition ‫كتٌر بٌجوا‬
Bracteole
A leafy structure from its axil arises a flower.
The flower is described as Bracteate.
When Absent:
Flower is called Ebracteate
e.g. Cruciferae
(Lama leaf teb2a soghayara
w tal3a mel flower)
Involucre
A scale-like (‫ )الزم أمسك عدسة عشان أشوفها‬leaf found
on the floral stalk.
The flower is described as Bracteolate
When Absent:
Flower is called
Ebracteolate e.g.
Foeniculum
Involucel
Group of bracts arranged in
one or more whorls just
below one flower (as
Nigela ‫ )حبة البركة‬or a group
of flowers (as Asteraceae)
Group of bracteoles arranged in whorls on the
floral axis e.g.
Apiaceae ‫عٌلة‬
‫البقدونس والٌنسون‬
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 Kinds of flowers
1- According to arrangement of floral leaves on the floral axis: (Rakezo 3ala cyclic w Acyclic)
Cyclic
the floral leaves of each whorl
alternate with those of the
next
e.g.:
Clove
Acyclic
The floral leaves are spirally
)‫(حلزونية‬arranged
e.g.: Cactus
Hemicyclic
The sepals and petals are in
whorls while stamens and
carpels are arranged spirally
e.g. Ranunculus
N.B.: In Chenopodiaceae, the perianth is spirally arranged, while stamens and carpels are in whorls
(Hemicyclic bardo)
2- According to the number of whorls present
Tetracyclic
Pentacyclic
Four Whorls
Five Whorls
3- According to the number of segments in each whorl
Dimerous
Two (rare)
Cruciferae
‫(العٌلة بتاعت‬
‫الجرجٌر‬
)‫والكرنب‬
Trimerous
Pentamerous
Three
Monocots
Five (most)
Dicots
4- According to the presence or absence of sexual organs
Complete (perfect) (Hermaphrodite)
E.g. Eugenia
Incomplete (imperfect)
Unisexual
e.g. Cannabis or Ray florets of
Sunflower
Staminate
Pistilate
Only Androecium
Neutral (Sterile)
E.g. Marginal
florets of
Sunflower
Only gynoecium
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5- According to the symmetry of all floral parts
Regular or Actinomorphic ‫منتظمة‬
Irregular ‫غير منتظمة‬
Segments are alike , regularly arranged. Could
be divided into equal
halves by a number of
radial longitudinal cuts
e.g. Rosa and Cloves
Segments are not alike, could not be divided
into equal halves
Asymmetric
Zygomorphic (%)
Segments could not
be divided into equal
halves (segments are
irregularly arranged)
e.g. Cactus
Could be divided into
equal halves in only
one plane e.g. ray
floret in Sunflower
Plane dividing it is
either transverse or
lateral  lateral or
transversely
zygomorphic
If plane is median 
Median zygomorphic
 Plants of Flowers
Monoecious ‫أوحادية المسكن‬
Both male and female flowers
on the same plant
- 1 house
E.g. Zea
Dioecious
Female and male flowers on
separate plants
- 2 houses
E.g.: Palms and Cannabis
Polygamous
Male, female and
hermaphrodite on the same
plant
E.g. Veratum
 Perianth
Outer non-essential floral parts when they are not differentiated into calyx and corolla (when all
the segments are alike in colour, texture, etc. as in many Monocots
May be described as:
Sepaloid Perianth
If thin membranous and greenish
Petaloid
If brightly coloured
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A- Calyx
Calyx
- It is the outermost whorl of the floral series.
- It is formed of 2-5 rarely numerous green sepals. May be:
Polysepalous or Aposepalous
With free sepals
e.g. Cruciferae
Gamosepalous or Synsepalous
With united sepals
e.g. Solanaceae
 Function:
Protects the essential organs of the flower especially in the bud.
 Petialoid
With brightly coloured sepals. Assuming the form and function of petals
 Sepals may be:
Foliaceous
Membranous
Large e.g. Rosaceae
Very small e.g.
Umbelliferae
‫شفاف وعامل زي الغشاء‬
Very small structure
E.g. Insect Flower
‫عٌلة البقدونس‬
Pappus
Absent
Kol sepal 3obara 3an hair Totally wanting
Rudimentary in a form of E.g. Chamomile
bristly hairs
E.g. Arnica
 Forms of Calyx:
‫ أما لو كانت‬oval, oblong, oblanceolate ‫بتمسك واحدة واحدة وتوصف فٌها‬free ‫ لو كانت‬sepal ‫لما ٌجٌلك ٌقولك اوصف‬
‫بتشوف أنهً فً دول‬United
Gamosepalous (united sepals)
1. Tubular
tube ‫عامل زي‬
2. Campanulate
‫عامل زي الجرس‬
3. Bilabiate
4. Urceolate
5. Glabose
6. Cup-shape
 Epicalyx:
Sepals are stipulate and stipules fuse in pairs
Bracts, bracteoles aggregated beneath the calyx
between the sepals producing an outer serious
forming the epicalyx.
of small sepal like structure.
(leaves stipulate or ‫فاكرٌن لما كنا بنقول‬
stipules ‫ نفس الحكاٌة أحٌانا بقى ال‬sepal )existipulate
epicalyx ً‫بتتحد مع بعض وتعمل‬
E.g. Rosaceae
E.g. Malvaceae 3elet el karkadeh
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B- Corolla:
Inner whorl of the floral envelope
Polypetalous or Apopetalous
Gamopetalous or Synpetalous
With free petals
With united petals
 Function
1- Attract the pollen carrying insects
2- Protect to certain extent the essential organs
 The corolla consists of delicate petals commonly arranged in:
Single whorl
Rarely double whorls
e.g. Papaver
Very rarely they are spirally
arranged e.g. Cactus
 Petals are commonly brightly coloured but some are:
Greenish in colour, sepaloid
Absent through abortion, apetalous
Modified into nectary dish
Chenopodum
Aconitum
Lauraceae
 Insertion of Corolla:
Hypogenous
Epigenous
Inserted on receptacle below
the ovary
e.g.: lavender
Superior
Ovary
Perigenous
Inserted on receptacle fused
with or closed over the ovary
e.g.: clove
Inferior Ovary
Inserted on hollow receptacle
that surrounds
the ovary but
does not fuse
with it
Superior ovary
 Colour of Petals
The petals are usually brightly coloured, this colour may be due to the presence of:
Anthocyanins
Red, Blue and Violet.
According to the change
in pH of the cellsap
Flavone derivatives
Yellow colour
Pigments
Other
Yellow, Orange and
Red
Such as carotene ,
xanthophyll
The white colour is due to
reflection of light from
the intercellular spaces of
the mesophyll but not to
pigments
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C- Androecium:
- The male sexual organ.
- It may consist of one, two or more (counting) of
stamens.
- Sometimes the stamens are numerous and
spirally arranged
- Androecium is situated within or above the
corolla
The complete stamen (microsporophyll)
consist of:
The filament
The Anther
corresponds to the leaf-stalk and bearing
special swollen pollen-producing structure,
called anther
filament ‫ ال‬leaf ‫ فً األصل‬stamen ‫احنا متفقٌن ان ال‬
‫ بعد ما اتعملها‬petiole ‫بقى هو الجزء اللً بٌمثل ال‬
modification
Corresponds to the blade (lamina) which is
much reduced. The anther is divided into two
anther-lobes. (el lobes de mortabata b ba3d by
a structure called connective which lies on the
back of the anther and corresponds to the
midrib of the leaf)
Each anther-lobe typically possesses two pollensacs containing numerous pollen-grains
(microspores)  Check Picture
 The Filament
Absent
Sessile
e.g. Viola
Equal
Most commonly of equal
length
Unequal )‫(ركزوا عليه‬
Didynamous Tetradynamous
Check Next Table
 Unequal Filaments:
Didynamous
2 Long, 2 Short stamens
e.g.: Labiateae - Lavender
Tetradynamous
4 Long, 2 Short stamens
e.g.: Cruciferae
 The Stamen
Stamonide: stamen which is esterile i.e. not producing pollen and thus called staminode e.g. Linum
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 Number of stamens:
Indefinite: When numerous spirally arranged and not readily counted e.g. Rose
Definite: When the stamens in the flower are few. They are five types:
Monandrous
e.g. Euphoria
Diandrous
e.g. Sallx
Triandrous
e.g. Iris
Tetrandrous
Pentandrous
e.g. Labiatae (2+2)
e.g. Belladonna
 Cohesion of stamens:
The term denoting the way of fusion of the stamens together is: (free or united)
→ by filaments or by anthers):
a- by filaments
- Monodelphous:
Filaments fused in one group e.g. Malvaceae
- Diadelphous:
Filaments fused in two groups e.g. Glycyrrhiza
- Tetradelphous:
Filaments fused in four groups e.g.: clove
- Polyadelphous:
Filaments fused in several groups e.g. Citrus
b- by anthers
-
Syngenesious:
Filaments free, but anthers cohere e.g.: Compositae (Asteraceae).
 Adhesion or adnation of stamens with othe floral parts:
Episepalous
Epipetalous
Adhesion between the
Adhesion between stamens
stamens and sepals
and petals
sepal‫ متحدة مع ال‬stamen ‫ ال‬e.g. Solanaceae, Asteraceae
Gynandrous
The stamens adhere to the
gynaecium
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