Sweet potato is a modified

The root system of sweet potato plants obtained by vegetative propagation starts with adventitious roots that develop into primary fibrous roots which branch into lateral roots. As the plant matures, thick pencil roots that become lignified are produced. Other roots without lignin, are fleshy and bulky and are called storage roots. Such roots are specialized to store food and get swollen in the process.

Plants are grown from true seed form a typical root system with a central axle with lateral branches. Later on, the central axle functions as a storage root.