In the event that the terminal bud should be injured or otherwise prevented from growing, these lateral buds are capable of producing a shoot. The solid stem structure of the corm is protected against injury and water loss by dry leaf bases that are similar to the tunic that enclose true bulbs. Gladiolus and watsonia are typical cormous plants. Unlike true bulbs and corms which are covered with dried leaves or scales, tubers are covered with a tough skin. Tuberous roots such as dahlia and ranunculus are true roots and lack nodes and internodes.
Buds are present only at the crown or stem end of the root.
Rhizomes are thickened horizontal stems growing along or below the surface of the ground. Underground rhizomes such as canna and calla produce roots on their lower surface and send shoots above ground. The term bulb will probably always be used when referring to plants that produce underground storage organs. My intent is to make you aware that all so called bulbs are not always true bulbs.