In angiosperms, flowers are arranged in a specific order in each plant. Some flowers like roses grow alone, and others grow in a group or cluster. This arrangement of a cluster of flowers on a stem which can be a single branch or system of branches is called an inflorescence where the main stem is called a peduncle.
Additionally, inflorescence can be classified into different types – racemose and cymose inflorescence, compound, special, mixed or verticillaster inflorescence. Each of these types is further classified into two other categories - determinate and indeterminate inflorescence.
In determinate inflorescence, young budding flowers can be found at the bottom, while in indeterminate inflorescence young buds are at the top. Racemose inflorescence falls under indeterminate category while cymose inflorescence is of determinate inflorescence type.
It is the type of inflorescence where growth of the main stem stops after the growth of a flower. The flowers are arranged in a basipetal sequence, which means that flowers start maturing from apex or the top and towards the base of its stem. Consequently, flowers in cymose inflorescence open in a centrifugal mode. It means that the flowers start opening from the centre to their periphery.
Cymose inflorescence can be further divided into four different groups which are a vital part of your curricula. These groups have been discussed in detail below, along with their individual subgroups and divisions–
Uniparous or Monochasial Cyme – In this case, the peduncle or main stem produces only one flower and stops growing. It produces one lateral branch at a time which also terminates after developing one flower and another succeeding branch at a time. Monochasial cyme can be classified into three types. They are –
Helicoid – In this type of uniparous cyme, the branches keep growing on the same side only and ultimately form a helix. Examples are Drosera, Hamelia, etc. Notably, there are two types of helicoid – drepanium and bostryx.
Scorpioid – when branches grow alternatively on both sides, it is known as monochasial scorpioid cyme. Two types of scorpioid include cincinnus and rhipidium.
Sympodial – It is a type of monochasial cyme where stems which are curved or zig-zag in the beginning but later on become straight and multiply to form the central axis.
Biparous or Dichasial Cyme – In this type of inflorescence, the main stem stops growing after the development of a terminal flower. However, two lateral branches originate from the main stem at the same time, and they too stop growing after producing a flower. The lateral branches may, in turn, produce two other branches. Examples of dichasial cyme include saponaria, jasmine, teal ixora and so on.
Polychasical or Multiparous Cyme – Here the central axis or peduncle ends in a flower called the terminal bud. Then from the base of this terminal flower, two or sometimes more than two lateral flower producing branches originate. This is also called simple polychasium. It looks similar to umbel type inflorescence, but the difference between the two is that terminal flower matures or opens first. Examples are calotropis, hamelia patens etc.
Cymose Capitulum or Head – In this type, the peduncle or the main stem is in the shape of a circular disk. The formation is similar to a raceme head. The flowers are either sessile or sub-sessile which are arranged in a centrifugal order like a globose head. The globose head is also known as glomerule. Some examples are acacia, albizzia.
The two main types of inflorescence are racemose and cymose. It is easy to confuse the characteristics of the two types and consequently, it is vital you note their differences. The table given below shows the differences between these two inflorescences. You can go through the table to quickly revise the main characteristic features.
NEET is an all India based examination which includes various topics like verticillaster inflorescence and others. The level of competition is quite high due to the considerable number of students that participate every year. Resultantly, you must be prepared with topics like racemose and cymose, and others to attain a good rank.
While it is natural to be nervous to some extent, it is imperative you try to stay calm during your examination. Among basic tips that you can follow to stay calm, meditation can be of great help. Also, appearing for mock tests during the run-up to the examination is vital. Furthermore, do not skip your rest since iIt will only make you more anxious.
Here’s wishing you good luck for NEET!
1. What is Cymose Inflorescence?
Ans. In this type of inflorescence, the young flower buds are at the bottom, and the older ones are at the top. Some cymose inflorescence examples are night jasmine, Drosera, common European elder etc.
2. What are the Different Types of Cymose Inflorescence?
Ans. The different types of the cymose inflorescence are as follows – monochasial cyme, dichasial cyme, multiparous cyme and cymose head.
3. What is the Primary Difference Between Cymose and Racemose Inflorescence?
Ans. In cymose inflorescence, the peduncle or the main stem shows a sympodial or multipodial growth while in the case of racemose inflorescence, it shows a monopodial growth.