Parsley is related to celery, carrots and parsnip, which all belong to the family Apiaceae (also Umbelliferae). Botanical names for parsley types are Petroselinum crispum (curly leaf parsley), P. neapolitanum (flat leaf parsley) and Petroselinum crispum subsp. tuberosum (root parsley).
Root parsley is not parsnip (Pastinaca sativa) even though they are used in a similar fashion in the kitchen. Root parsley has a milder, sweeter taste than parsnip. You may substitute parsnip in recipes that call for root parsley, however.
Likewise, flat or Italian parsley has a sharper taste, with more essential oils than curly leaf, but can be used interchangeably, as taste allows.
Parsley, a Mediterranean plant, came to Germany via Roman Legionnaires as the Roman Empire expanded. It was cultivated in German and French medieval cloister gardens as a medicinal plant and was rumored to cure all kinds of illnesses and symptoms. In modern times, it is reputed to have antioxidants and anti-tumor substances. It is primarily eaten raw, sprinkled over a dish right before serving or added just at the end of cooking time. In many German recipes, raw parsley is mixed with a meat farce and cooked. It is also used in most bouquet garni bundles, which are cooked the entire time in the liquids and discarded before finishing the dish.
It is a major component of Italian gremolata as well as sprinkled over salt potatoes or "Dampf-" or "Pellkartoffeln", as an ingredient of German Green Sauce and used in "Suppengrün".
I like to use parsley root cooked and mashed with butter, salt and pepper. Small portions (about 1/4 cup) on a plate complement most roasts and mashed potatoes.
