3. Arrangement of flowers
1.Calyx
Calyx is a cup shaped structure.
It is found at the bottom of all the other parts. It consist
of sepals.
Sepals are similar to small green leaves.
Colourful sepals can be in some flowers.
Function of the calyx is the protection of tender the
flower bud.
Photosynthesis takes place in green in coloured sepals
Colourful sepals are important to attract insects for
pollination
4. Image for calyx flowers
Musandas Sesbenia Tribulus
Rose Musandas Muntingia
5. 2.Corolla
Within the calyx are the whorl of floral leaves
called petals, together and forming the corolla.
It is the most beautiful and attractive part of the
flower.
The corolla protects the internal parts of flower
and also helps to attract insects for pollination.
The corolla is colourful in majority of flowers
which are pollinated by insects
Corolla shows diversity in colour and shape
7. In most of the flowers which bloom during the
night, the corolla is white in colour and the flowers are
scented.
This is also important to attract insects for pollination
Coral jasmine Getapichcha Kadupul
8. 3.Androecium
Androecium is the male part of a flower.
It is the whorl of floral leaves found inside
the corolla.
Androecium consists of stamens.
A stamen consists of the another and the
filament.
The function of the androecium is to produce
and release pollen grains.
Stamens of flowers can be independent or
connected to the petals.
9. Image for androecium flowers
Brassica Shoe flower Torneia
Gloriosa Passion fruit Calotropis
10. 4.Gynoecium or pistil
Gynoecium or pistil is the female part
of a flower.
It is the innermost part of a flower .
It consists of three parts namely
stigma, style, and ovary.
The stigma is situated at the top and
the ovary is situated at the base.
The style is a tube like structure which
connects the stigma and the ovary.
Ovules can be seen in the ovary.
After pollination the ovary becomes
the fruit and the ovules become seeds.
11. 5.Bisexual flowers
If the both gynoecium (pistil)
and the androecium are present in a
flower it is called a bisexual flower.
Examples for bisexual flowers.
Blue lily
Shoe flower Sesbenia Casealpinia
12. 6. Unisexual flowers
In some flowers only one of
these two parts are present. Such
flowers are called unisexual flower.
Examples for unisexual flowers.
Coconut flowers
13. Symmetry of flowers
1. Radially symmetrical flowers or an actinomorphic
flowers.
If a flower can be divided into
two similar halves by cutting
vertically through any one of its
axis which passes through the
centre, such flowers are known as
radially symmetrical flowers or
an actinomorphic flowers.
15. 2. Zygomorphic flowers
Some flowers can be divided into
two similar halves by cutting along
only one symmetrical axis.
These flowers can be known as
bilaterally symmetrical flowers or
zygomorphic flowers.
16. Image for Zygomorphic flowers
Salvia Leucus zeylaniea Crotolaria
Thunbergia Sesbenia Caesalpinia
17. 3. Asymmetrical flowers
Some flowers cannot be divided into two
similar halves by cutting along any axis.
These flowers are known as irregular or
asymmetrical flowers.
Species of cactus
Examples for such flowers.
Species of cactus Species of cactus Species of cactus
18. Structure of flowers
There are some standard methods
to describe the structure of flowers.
They are
Whole flower
Half flower
Floral diagram
19. 1. Whole flower
By observing a flower
externally we can study
structure of the flower.
To observe the
colour, nature, its parts and
their position in the flower by
the naked eye one has to
observe a whole flower
20. 1. Half flower
To observe the parts of a flower
more clearly we can separate a flower
into two similar halves through a
symmetrical axis of the flower
Because some parts which cannot
be seen by observing the flower
externally clearly seen in a half
flower.
Therefore a half flower is used to
describe the structure of a flower.
Half flower can be depicted by a
line.
21. 3. Floral diagram
A transverse section drawn so
that all the parts of the flower are
in the same level is called a floral
diagram.
This is similar to a diagram of a
flower drawn as seen from the top.
To draw a floral diagram the
main axis of the tree should placed
the anterior side and the bract
should placed to the posterior side.
Position of a flower in the tree
Floral diagram of flower
22. 1) If the both gynoecium and androecium are
present in a flower it is known as
Corolla of the flowers
Unisexual flowers
Calyx of the flowers
Bisexual flowers
23. 2)If a flower can be divided into two similar halves by
cutting vertically through any one of its axis which
passes through the center such flowers are known as
Androecium
Zygomorphic flowers
Actinomorphic flowers
Asymmetrical flowers
