Due to the storage of food, in many plants the taproots become swollen and take various forms. Modifications of tap root system can vary and may be of the following types:
1. Fusiform - This root is widest (swollen) in the middle and gradually tapers towards the top and the bottom: Example: THE RADISH (RAPHANUS SATIVUS)
2. Napiform - This root has a top-like (spherical, ball-shaped) appearance. It is very broad at the top and tapers down (suddenly like a tail at the bottom) Example: TURNIP (BRASSICA RAPA)
3. Conical - This type of root has a cone-like shape, widest at the top and tapering smoothly towards the bottom. Example: CARROT (DAUCUS CAROTA)
4. Tuberous - This type of root is thick and fleshy (scattered along the length) for food storage and look like tubers. It has no definite shape. Example: CASSAVA (MANIOC), MIRABILIS EXPANSA
Images: http://en.wikipedia.org/
