A corm is the swollen base of a stem axis enclosed by dry scale-like leaves that form a protective tunic.
Elephant's ear (Alocasia)
A corm is a solid stem structure with distinct nodes and internodes.
In contrast, a bulb's interior is predominantly leaf scales and its stem is the compressed basal plate.
Some species like crocus and gladiolus, produce a corm that is an annual structure (old corm) replaced with a new corm each year.
Cormels form at the base of the new corm and are a natural form of multiplication.