When you eat celery, do you eat the leaves?
If you eat celery, you almost certainly eat the leaves. Why? Because the part of celery that we think of as the stalks are actually part of the leaves called the petiole. When you look at a leaf from most trees, the petiole is the stalk-like part that connects the flat part of the leaf to the stem. In the case of celery, the petioles connect directly to the base of the plant.