The number of stamens of a flower is 3 or a multiple of 3 is called Trimerous. Flowers of monocots are trimerous. For example – rosin, rice, wheat etc.

(i) Trimerous: The number of stamens of a flower is 3 or a multiple of 3 is called Trimerous. Flowers of monocots are trimerous. For example – rosin, rice, wheat etc.
(ii) Tetramerous: The number of stamens of the flower is 4 or a multiple of 4 is called Tetramerous. Flowers of dicotyledonous plants are Tetramerous. For example, paint.
(iii) Pentamerous: The number of stamens of a flower is 5 or a multiple of 5 is called Pentamerous. Flowers of dicotyledonous plants are pentamerous. For example – Jawa.

Out of six stamens four are long and two are short then it is called Tetradynamus.

If out of four stamens two are long and two are short then it is called Didynamus.

(i) Didynamus: If out of four stamens two are long and two are short then it is called Didynamus.
(ii) Tetradynamus: Out of six stamens four are long and two are short then it is called Tetradynamus.

A flower which divides along the axis to produce multiple equal parts is called a polysymmetric flower. For example – dhotura, jaba, brinjal, mustard etc.

A flower which can be divided into two equal parts once along the axis is called a symmetrical flower. For example- Beans, Buckwheat, Atsi, Beans, Aparajita etc.

A flower which cannot be divided into two equal parts along the axis in any way is called asymmetric flower. Like- Kalabati, Orchid, Sarvajaya etc.

There are three types of flowers according to symmetry
(i) Asymmetric: A flower which cannot be divided into two equal parts along the axis in any way is called asymmetric flower. Like- Kalabati, Orchid, Sarvajaya etc.
(ii) Zygomorphic: A flower which can be divided into two equal parts once along the axis is called a symmetrical flower. For example- Beans, Buckwheat, Atsi, Beans, Aparajita etc.
(iii) Actinomorphic: A flower which divides along the axis to produce multiple equal parts is called a polysymmetric flower. For example – dhotura, jaba, brinjal, mustard etc.

A flower which has neither stamens nor pistils is called Cliblinga flower. It beautifies.