1. Production of new plants from the vegetative parts such as stem, root, leaves of the existing plant is called vegetative propagation. 

2. Aerial weak stems like runners and stolons, when they touch the ground, give off adventitious roots. 

3. When the connection with the parent plant is broken, the portion with the newly struck roots develops into an independent plant.

4. Some examples for propagation by stem are from stolons, bulbs, corms and tubers as follows. 

a) Stolons – Vallisneria, Strawberry 

b) Bulbs – Alliumcepa or onion 

c) Corms – Colacasia 

d) Tuber – Potato