Diversity of flowers
Transcript of Diversity of flowers
DIVERSITY OF FLOWERS
Parts of flowers
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 sepalsColourful sepals are important to attract insects for
pollination
Rose
Musandas
Musandas Muntingia
Sesbenia Tribulus
Image for calyx flowers
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
Clitoria
AlstoniaCatharnthusOrchid
WrightiaShoe flower
Image for corolla flowers
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
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.
Brassica
CalotropisPassion fruitGloriosa
TorneiaShoe flower
Image for androecium flowers
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.
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.
Shoe flower Sesbenia Casealpinia
Blue lily
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
Symmetry of 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.
1. Radially symmetrical flowers or an actinomorphic flowers.
Image for Actinomorphic flowers
Shoe flower WrightiaTemple flower
Catharnthus KaduruPumpkin
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.
Image for Zygomorphic flowers
Salvia
Sesbenia CaesalpiniaThunbergia
CrotolariaLeucus zeylaniea
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.
Examples for such flowers.
Species of cactusSpecies of cactus
Species of cactus
Species of cactus
Structure of flowers
There are some standard methods to describe the structure of flowers.
They areWhole flowerHalf flowerFloral diagram
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
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.
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 treeFloral diagram of flower
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
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
3)Example for asymmetrical flower is
Orchid
Sesbenia
Cactus
Rose
4)Example for actinomorphic flower is
Pumpkin
Cannon ball tree
Coconut flower
Lotus
3)Example for zygomorphic flower is
Caesalpinia
Shoe flower
Passion fruit flower
Gloriosa
U.VinusanJaffna Hindu College
Grade 9
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