The underground stems are modified plants that perform a variety of functions.
Rhizomes, tubers, maize, and bulbs are examples of underground stems. Only some sections of underground stems are edible; the entire stem is not edible.
Onion and garlic are two other examples.
The bulb is generated by multiple nodes in the condensed stem overlapping. The mushy and scaly leaves will be linked to a thickened base on the bulb.
The tunic is a dry, protective covering for the thick and scaly leaves. We can consume the meaty and scaly interior leaves.
A form of the underground stem is the tunic. The tunic is a covering of membrane scales that covers the tunicated bulb. The tunic is a non-edible dried coating over the fleshy leaves of the bulb, similar to the skin we remove from onions and garlic.