Parsley, scientifically known as Petroselinum crispum, is a widely used herb in culinary practices. It comes in two main varieties: curly leaf parsley and flat-leaf (Italian) parsley. Both varieties have bright green leaves and a fresh, slightly peppery flavor.Parsley, scientifically known as Petroselinum crispum, is a widely used herb in culinary practices. It comes in two main varieties: curly leaf parsley and flat-leaf (Italian) parsley. Both varieties have bright green leaves and a fresh, slightly peppery flavor.