Cymose Inflorescence

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What is Inflorescence?

The inflorescence is a particular fashion in which a cluster of flowers is arranged on the stem or the floral axis. Morphologically, it is the part that is modified from a shoot in angiosperms where flowers are formed. It can also be defined as the reproductive part of the plant that bears the group or cluster of flowers in a particular fashion. The stem that holds the inflorescence is termed as the peduncle and the one which is the major axis that holds the inflorescence or other branches is called the rachis. The stalk of each flower in an inflorescence is called a pedicel.

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There may be a flower that is not part of the inflorescence, that stands as a solitary flower and the flowers in the inflorescence are referred to as florets. Flowers turn into fruits we already know and the stage at which it occurs in the inflorescence is known as infructescence. Inflorescence can either be simple or complex. Depending on this, there are various types of inflorescence- Simple inflorescence is of two types- Racemose inflorescence and Cymose inflorescence. The other types of the inflorescence are- Hypanthodium, Cyathium, Verticillaster.


Types of Inflorescence

Simple Inflorescence

  • Racemose- It is a simple type of inflorescence in which the main axis continues to grow and flowers are borne laterally in an acropetal succession on the axis.

  • Cymose- It is another simple type of inflorescence in which the termination of growth of the main axis occurs and the flowers are borne in a basipetal succession. Thus, in this case, the main axis shows limited growth.

Other Inflorescence

  • Hypanthodium: The main axis forms a cup-shaped structure that has a cavity which holds male and female flowers and a small apical opening.

  • Cyathium: In this case involucre of bracts forms the cup-shaped structure. A Single flower is present in the middle surrounded by male flowers.

  • Verticillaster: This type of inflorescence is seen in plants with opposite leaves. The two exiles of leaves give rise to two clusters of sessile flowers. Each cluster of flowers shows a dichasial cyme arrangement.


Let’s study Cymose Inflorescence in Detail in this Chapter.

Cymose Inflorescence

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The cymose inflorescence is also known as determinate inflorescence and is characterized by the presence of a flower at the apex of the floral axis. The main axis has limited growth in this case. The lateral axis terminates into a flower and limits the growth of the axis. Flowers are arranged in basipetal succession in this type of inflorescence. Thus, younger flowers are present at the base and the older flowers are placed terminally on the axis. This arrangement is also called a centrifugal arrangement with the older flowers in the middle and the younger ones present in the periphery.


Types of Cymose Inflorescence

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There are basically four main types-

1. Monochasial Cyme: It is also called a uniparous cyme in which the main axis terminates in a flower and it produces one lateral branch from the base, which also terminates in a flower. Each lateral and subsequent branch gives rise to a lateral branch with a terminal flower. This type of cymose inflorescence is further divided into two types:

  • Scorpioid: On both sides of the axis, lateral branches are developed. Example- Sundew

  • Helicoid: Lateral branches form a helix structure by growing on the same side. Example- Begonia

2. Dichasial Cyme: It is also called a biparous cyme in which the terminal peduncle terminates in flower. It grows into two lateral branches with terminal flowers. Subsequent branches also grow in a similar pattern. Example- Jasmine.

3. Polychasial Cyme: It is also called a multiparous cyme because multiple branches arise at the base of the apical flower on the peduncle. The oldest flower is placed in the middle of the axis. Example- Calotropis

4. Cymose Capitulum: The peduncle is reduced to a circular disc in this type of inflorescence. Thus, the older flowers are at the center of the disc and the younger flowers grow at the periphery. This is also called a centrifugal arrangement. Example- Mimosa, Acacia, etc.

FAQ (Frequently Asked Questions)

1. What is Cymose Inflorescence?

Ans. The cymose inflorescence is also known as determinate inflorescence and is characterized by the presence of a flower at the apex of the floral axis. The main axis has limited growth in this case. The lateral axis terminates into a flower and limits the growth of the axis. Flowers are arranged in basipetal succession in this type of inflorescence. Thus, younger flowers are present at the base and the older flowers are placed terminally on the axis. This arrangement is also called a centrifugal arrangement with the older flowers in the middle and the younger ones present in the periphery.

2. What is the difference between Racemose and Cymose Inflorescence?

Ans. In cymose inflorescence, the main axis terminates in a flower and has definite growth. The peduncle shows multipodial growth and the flower is present apically in basipetal succession. The arrangement of flowers is in centrifugal pattern and the first flower blooms at the tip of the peduncle.


On the other hand, in racemose inflorescence, the main axis continues to grow indefinitely. The peduncle has monopodial growth and the flowers are present laterally in acropetal succession. The arrangement of flowers is centripetal in this case. The first flower blooms at the base of the peduncle.


The number of flowers is definite in the cymose inflorescence with the flowers blooming at a long interval but in racemose the formation of flowers is indefinite and the flowers bloom at short intervals.

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3. What are the types of Cymose Inflorescence?

Ans. There are four main types of cymose inflorescence:

  1. Monochasial cyme

  2. Dichasial cyme

  3. Polychasial cyme

  4. Cymose capitulum