Floral parts and their structure:
All floral parts develop from thalamus from different nodes.
From each node of thalamus circle or whorl of modified leaves is produced.
Thalamus is called as torus or receptacle. Thalamus is green in colour hence it can perform the process of photosynthesis.
1. Calyx (K) :
It is outermost floral whorl and individual members are known as sepals.
Sepals are usually green in colour and perform photosynthesis.
If all the sepals are united, the condition is gamosepalous and if they are free, the condition is called as polysepalous.
Gamosepalous calyx is found in china rose and polysepalous calyx is found in Brassica.
The main function of sepals is to protect inner floral parts in bud condition.
Sometimes sepals become brightly coloured (petaloid sepals) and attract insects for pollination
e.g. Canna, Mussaenda etc.
Calyx i.e. Sepals modify into hairy structures called as pappus.
Such calyx helps in dispersal of seeds or fruits. E.g. Sonchus.
|
Type of Calyx |
Nature of Sepals |
Examples |
|---|---|---|
|
Caducous |
Sepals fall off as soon as the flower bud opens |
Argemone (Poppy) |
|
Deciduous |
Sepals survive till (withering of petals) fruit formation |
Lotus, mustard |
|
Persistent |
Sepals remain even after fruit formation |
Brinjal, Pea |
2. Corolla (C):
It is second floral whorl from outer side and variously coloured.
The individual member is calledas petal.
Petals may be sweet to taste, posses scent, odour, aroma or fragrance etc.
The condition in which petals are free is said to be polypetalous (e.g. Rose) and if they are fused it is called as gamopetalous (e.g. Datura).
The main function of corolla is to attract different agencies for pollination.
Perianth (P) :
Many times calyx and corolla remain undifferentiated.
Such member is known as tepal. The whorl of tepals is known as Perianth.
If all the tepals are free the condition is called as polyphyllous.
If they are fused the condition is called as gamophyllous.
Sepaloid perianth shows green tepals while petaloid perianth brightly coloured tepals. E.g. Lily, Amaranthus,Celosia,etc.
It protects other floral whorls. Petaloid tepal helps in pollination and sepaloid tepals can perform photosynthesis.
