Study of Different Types of Inflorescences

Our Objective 

To study the different types of inflorescences. 

 

The Theory 

Inflorescences 

Inflorescence means the arrangement of flowers on the floral axis/main, axis/peduncle and it includes the timing of flowering (determinate and indeterminate). “Indeterminate” inflorescences are those that have the youngest flower at the end of the main axis (rachis) (i.e., terminal bud continues to produce new flowers). “Determinate” inflorescences are those that have the oldest flower towards the end of the main axis (i.e., terminal bud stops growing and lateral flowers are produced from axillary buds.) 

Types of Inflorescences 

There are two types of inflorescences they are 

  • Racemose 
  • Cymose 

Racemose - On the floral axis the flowers branch laterally. The flowers here continue to grow along the floral axis and they develop in an acropetal shape.  

Cymose - In cymose the flowers are in the terminating point of floral axis. The flowers in the cymose inflorescences are basipetal shape. 

 

                                                                                                

 

Types of Racemose

Raceme – The flowers are pedicellate when the peduncle is elongated, e.g., Mustard. 

Spike – The flowers are sessile but the peduncle is elongated, e.g., Barley.

Catkin – The flowers are sessile and unisexual. The peduncle is thin, long, and weak, e.g., Mulberry. 

Spadix – The flowers are small, sessile, and unisexual. The peduncle is thick, long, and fleshy, e.g., Banana. 

Corymb – The flowers are present at the same level because of the lower flower has much long pedicle than upper one. The peduncle is short, e.g., Candytuft. 

Umbel - The flower stalks are of equal in length, arise from the same point, e.g., Coriander. 

Capitulum – The flowers are sessile and the peduncle is flattened, e.g., Sunflower. 

Panicle – The main axis is branched then it is called as compound raceme, e.g., Mango. 

 

                                                                         

 

Types of Cymose

Monochasial cyme – A single flower arises in the axil of a leaf of an ordinary shoot or the peduncle, ends in a single flower, e.g., Hibiscus 

Dichasial cyme – They consists of only three flowers, out of which the central one is the oldest and the two lateral ones arising in the axils of bracts below the older flower which are youngest, e.g., Jasmine 

Polychasial cyme - The main axis ends in a flower with more than two branches arising from the peduncle below the terminal flower, e.g., Calotropis.  

 

                                                                               

 

Ovary position of the flower 

Epigynous – This is a type of flower the floral parts are located above the ovary and the ovary is present in the deep location of the flower. It is called an inferior ovary where the floral parts are attached at the top of the ovary. Examples of epigynous flower is apple (Mallus) etc. 

Perigynous - This is a type of flower the floral parts are attached to the ovary almost at the mid part with the help of a cup shaped structure called as hypanthium. Hypanthium is inserted below the ovary. The ovary is semi superior. Examples of such flowers are rose etc. 

Hypogynous - This is a type of flower the floral parts are attached to the lower side of the ovary to the receptacle. Hence the ovary is superior with respect to floral parts like sepal, petal, stamen etc. Examples of such flowers are mustard etc.                                                  

      

Learning Outcomes 

  • Students understand the term Inflorescences and its types. 
  • Students understand the ovary position in each flower. 
  • Students can come to know about locally available inflorescence around their surroundings.