Phyllody is the abnormal development of floral parts into leafy structures. It is generally caused by phytoplasma or virus infections, though it may also be because of environmental factors that result in an imbalance in plant hormones. Phyllody causes the affected plant to become partially or entirely sterile, as it is unable to normally produce ...
A change of floral petals (leaves) to foliage leaves. 
• (n.) A retrograde metamorphosis of the floral organs to the condition of leaves.
The replacement of floral parts by leaf-like structures.
Phyl'lo·dy noun [ See Phyllodium .] (Botany) A retrograde metamorphosis of the floral organs to the condition of leaves.