Chapter-5Morphology of Flowering Plants ( INFLORESCENCE)

Presented by B.Prabhakar

PrincipalJNV. Panchmahal (Guj)

Parts of the plant• 1. Roots • 2. Stem• 3. Leaves• 4. Flower

• Specify the part of the plant which is useful for the sexual reproduction

• Ans. Flower

• Is the flower single in all the plants

• Ans. No• Then how are flowers arranged• Ans. They are arranged singly

or in groups

• The technical name for the cluster of flowers is called

• Inflorescence

Structure of the inflorescence• Stalk of the inflorescence is called

Peduncle• Stalk of the flower is called Pedicel

• The flower which has stalk is said to be Pedicillate flower

• The flower without stalk is said to be sessile flower

Pedicillate & Sessile flowers

Types of Inflorescence

• 1. Racemose inflorescence• 2. Cymose inflorescence

Racemose inflorescence

• 1. The growth of the inflorescence axis is unlimited

• 2. Flowers are arranged in Acropetal manner

Flowers may be sessile or pedicillate

Types of racemose inflorescence

• 1. Raceme• 2. Spike• 3. Spadix• 4. corymb• 5. Umbel• 6. Capitulum

Raceme• 1. Flowers have pedicels• 2. Flowers are arranged in Acropetal

manner

Flower

Acropetal arrangement• Older flowers are

present at the base& Younger flowers are present at the top

Ex- Mustard

Spike• 1. Flowers are

without pedicels• 2. Flowers are

arranged in acropetal manner

Flower

http://www.pssc.ttu.edu/techhort/IMAGES/flowers/spike.jpg

Spadix

• If the spike is covered by spathe , it is called Spadix

Ex – Banana

Coconut

Corymb• Flowers have

pedicels

• All flowers brought to the same place though they originate from the different places

• Pedicels are in different lengths

Pedicel

Umbel• Flowers

originate from the same place & they reach to the same level

Head inflorescence

A head (capitulum) is a short dense spike in which the flowers are borne directly on a broad, flat peduncle, giving the inflorescence the appearance of a single flower

Ex – Sun flower, Chrysanthemum, Marigold

Structure of Head inflorescence

• It has two types of florets.

• 1. Ray florets

• 2. Disc florets

Ray Floret

Ray florets are the female florets

They are said to be

Pistillateflowers

They have only Gynoecium

Androecium is absent

Disc florets are bisexual floretsThey have both Stamens & pistil

Racemose inflorescence

Cymose inflorescence

• The growth of the inflorescence axis is limited

• Flowers are arranged in basipetal manner

Basipetal arrangement

• Older flowers are present at the top , younger flowers are present at the base

Types of cymose inflorescence

• 1. Uniparous or Monochasial• 2. Biparous or Dichasial• 3. Multiparous Polychasial

1. Uniparous or Monochasial cyme

In this type of inflorescence, the peduncle ends in a flower. Subsequently one branch of the peduncle develops at a lower level and ends in a flower. This type of branching is repeated.

Uniparous cyme

What is the difference between these two

If the branches are produced on the same side, the inflorescence is said to be a monochasial helicoid cyme. e.g. Hamelia, Drosera.

If the branches are produced alternately in a zigzag manner, the inflorescence is called a monochasial scorpioid cyme. e.g. Heliotropium.

Biparous cyme In this type of cymose inflorescence, the peduncle produces a flower at its tip, subsequently the peduncle produces two branches simultaneously at a lower level. They also end in flowers. This type of branching is repeated.

Polychasial cyme

• In this type of inflorescence the main axis ends in a flower. Subsequently the peduncle produces many branches and each branch ends in a flower.

Ex- Calotropis

Identify the following inflorescences

Identify the following inflorescences

What do you call this inflorescence