Presentation on Inflorescence

7/27/2019 Presentation on Inflorescence

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WELCOME


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INFLORESCENCE


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INFLORESCENCE

A group of flowers which are variously clustered together is calledinflorescence.

The axis of the inflorescence is called peduncle.

The stalk of the flower is called pedicel.

The inflorescence may be divided into 2 main groups.

RACEMOSE

CYMOSE


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1: Racemose Inflorescence(Indefinite inflorescence)

In this inflorescence, peduncle grows indefinitely and the flowers arearranged In an acropetal succession or the flowers are arranged in acentripetal manner.

Racemose inflorescence are classified into seven groups based on the natureof the branching of peduncle and the presence or absence of pedicels.


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a) Simple Raceme

Racemose inflorescence in which thepeduncle grows indefinitely and thepedicellate flowers arranged in anacropetal succession

Eg: Crotalaria


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b) Spike

Racemose inflorescence in which the sessileflowers are arranged in an acropetalsuccession

Eg: Achryanthes, Amaranthus, etc.


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c) Catkin

Pendulous spike with unisexual flowers.

Also called amentum.

Eg: Acalypha, Morus, etc.


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d) Spadix

Spike with a fleshy axis, which is enclosedby brightly coloured bracts, calledspathe, as in banana, palms, anthuriumetc.


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e) Corymb

Here the main axis is comparativelyshort, and older flowers have muchlonger pedicel than the youngerones.

All flowers are brought to the samelevel.

Eg: Caesalpinia


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f) Umbel

Racemose inflorescence in whichpeduncle is shortened.

The pedicellate flowers arise from thetip of the peduncle in centripetalsuccession.

In the umbel, there is an involucre of

bracts seen at the apex of peduncle.

Eg: Biophytum


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g) Head or Capitulum

Peduncle becomes modified intoreceptacle and may be flat,convex, or conical in shape, onwhich the small sessile flowers arearranged in centripetal succession.

The flowers in the head

inflorescence are called florets


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2. Cymose Inflorescence In this inflorescence, the main axis or peduncle ends in a flower.

Further growth of the axis is carried out by one or more branches.

Each branch ends in a flower. In this way, the successive branches end inflowers. So the older flowers are seen at the top and younger flowers arearranged laterally towards the base.

This type of development is called basipetal succession.

Sometimes the flowers are arranged in a centrifugal manner(older flowersat the centre and younger flowers towards periphery.


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a) Simple Cyme

Cymose inflorescence in which theaxis of the inflorescence ends in aflower.

From the axis, two lateral branchesopposite to one another develops.

Each branch ends in flowers. Thus the

inflorescence with three flowers, ofwhich older one is at the top, andyounger ones are towards lateralbranches.

Eg: Jasminum


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b) Monochasial Cyme

It is a Cymose inflorescence.

Differs from dichasial cyme in having a solitarylateral branch developed only at one side of thepeduncle. It is of 2 types.

Helicoid Cyme: Successive lateral branches aredeveloped only on one side of the peduncle. Eg:

Hamelia Scorpioid cyme: Successive lateral branches are

developed alternately on both sides of peduncle.Eg: Heliotropium


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c) Dichasial Cyme

In this, Peduncle terminate in an olderflower. The peduncle develops twolateral branches which arises from the axilof the bract of the oldest terminal flower.

The lateral branch develops into simplecyme composed of three flowers.

Eg: Dianthus


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d) Polychasial Cyme

In this the peduncle ends in flower.From the peduncle two or morelateral branches develop that endsin flowers.

Each lateral branch may bebranched once or several times.

Eg: Viburnum


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Thank You..

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Presentation on Inflorescence