When you cut flowers for a bouquet, you are generally cutting the peduncle. Peduncles are simply flowering stems, but they may surprise you.
Peduncles can occur in plants without stems, they may continue to grow indefinitely, and some peduncles grow underground.
The peduncle of a simple flower is easy to recognize. It is the classic stem you hold, cut, or put into a vase to admire. Its job is to support the flower. An artichoke stem is a peduncle, and for the same reason.
Now you know.
You can grow a surprising amount of food in your own yard. Ask me how!