The corm is a relatively solid modified stem that has a few fleshy leaves. In the photo, the upside down crocus corm has a black line drawn on it to emphasize the point of attachment of a leaf. The presence of nodes and internodes makes the corm a modified stem. The papery tunic on the outside of a crocus corm is the dead petiole from last year's leaf. Corms develop flowering stems which elongate after a cold period to emerge from the soil and expand their flowers.
Corms also have a nonpersistent root system that lives only one season.
The root system regenerates itself in the fall. Corms purchased at a store have no obvious root system. However, when planted, adventitious roots develop quickly.