From the Asteraceae family (in the thistle group) the Catalogue of Life lists two subspecies of Cynara cardunculus: Cynara cardunculus subsp. flavescens found predominantly in the western Mediterranean and Cynara cardunculus subsp. cardunculus, found in the east, with both subspecies reportedly overlapping in Sicily. Morphologically the main difference between the two comes down to the shape and colouring of the bracts (the leaf like projections shown in the picture).
The wild variety of the species is often referred to by the common name Cardoon, and the cultivated varieties that we buy in the supermarket as globe artichokes. The vegetable that we eat is the immature flower head which includes the bracts, the base known as the heart, and the middle area made of a mass of immature florets called the beard or the choke, which if left to grow would bloom into the purple flower head seen in the picture. The beard is generally discarded apart from in baby artichokes where the whole thing is eaten.