The water chestnuts we eat are the stems of the water chestnut plant, which are bulbs.

Stems have very important characteristics:

1. There are nodes. There are obvious nodes on the water chestnut;

2. There are buds. There will be buds on the top and sides of water chestnuts;

3. There are leaves on the stems. The membrane-like structure on the water chestnut is the leaf of the water chestnut.

So, water chestnuts are stems.