Broccoli is part of the cabbage family. Broccoli is a green vegetable that resembles small trees. The stalks and flower-like heads can all be eaten. There are three common varieties of broccoli: sprouting, calabrese, and romanesco. Broccoli was first seen in Italy. Broccoli contains high amounts of vitamin C and soluble fiber. It also contains nutrients such as diindolylmethane and selenium. Broccoli helps boost the immune system among other activities.