The parent organism can be divided into many pieces called fragments.
Each piece will develop into a complete individual.
A great example of fragmentation can be seen in spirogyra.
Spirogyra is a green alga that floats freely on freshwater ponds. Under a microscope, it can be seen as a rectangular cell with a nucleus in the vacuole located in the centre.
The rectangular cells are joined together in long strands called a filament.
When a filament is divided into many pieces, each piece will grow into individual filaments.