Figure 1: A large bunch of flat leaf parsley.
"Parsley, or Garden Parsley for precision (Petroselinum crispum) is a species of Petroselinum in the family Apiaceae, native to the central Mediterranean region (Iran, southern Italy, Algeria and Tunisia), naturalised elsewhere in Europe, and widely cultivated as a herb, a spice and a vegetable.
The two main groups of parsley used as herbs are curly leaf (P. crispum Crispum Group; syn. P. crispum var. crispum) and Italian, or flat leaf (P. crispum Neapolitanum Group; syn. P. crispum var. neapolitanum); of these, the Neapolitanum Group more closely resembles the natural wild species. One of the compounds of the essential oil is apiol. Flat-leaved parsley is preferred by some as it easier to cultivate, being more tolerant of both rain and sunshine, and has a stronger flavour while curly leaf parsley is preferred by others because of its more decorative appearance in garnishing."