Fiddlehead

Fiddleheadsorfiddlehead greensare the furledfrondsfrom a fledglingfern,harvested for use as avegetable.
Left on the plant, each fiddlehead would unroll into a newfrond(circinate vernation). As fiddleheads are harvested early in the season, before the frond has opened and reached its full height, they are cut fairly close to the ground.
Fiddleheads frombrackenscontainptaquiloside, a compound associated withbracken toxicity, andthiaminase.Not all species contain ptaquiloside, such asDiplazium esculentum, a fern with fiddleheads regularly consumed in parts of East Asia, which differs from bracken (Pteridium aquilinum).
The fiddlehead resembles the curled ornamentation (called ascroll) on the end of a stringed instrument, such as afiddle. It is also called acrozier, after thecurved staffused bybishops, which has its origins in theshepherd's crook.
The fiddleheads of certain ferns are eaten as a cookedleaf vegetable. The most popular of these are:
Fiddleheads' ornamental value makes them very expensive in the temperate regions where they are not abundant.
Available seasonally, fiddleheads are both foraged and commercially harvested in spring.When picking fiddleheads, it is recommended to take only one third the tops per plant/cluster for sustainable harvest.Each plant produces several tops that turn into fronds.
Fiddleheads have been part of traditional diets in much of NorthernFrancesince the beginning of the Middle Ages,acrossAsia,and also amongNative Americansfor centuries.They are also part of the diet in theRussian Far Eastwhere they are often picked in the wild in autumn, preserved in salt over winter, and then consumed in spring.
In Indonesia, young fiddlehead ferns are cooked in a rich coconut sauce spiced withchili pepper,galangal,lemongrass,turmericleaves and other spices. This dish is calledgulai pakisorgulai paku, and originated from theMinangkabauethnic group ofIndonesia.
In thePhilippines, young fronds ofDiplazium esculentumorpakôis a delicacy often made into a salad with tomato,salted eggslices, and a simple vinaigrette dressing.
In East Asia, fiddleheads of bracken (Pteridium aquilinum) are eaten as a vegetable, calledkogomi(コゴミ) in Japan,gosari(고사리) in Korea, andjuécài(蕨菜) in China andTaiwan.
InKorea, a typicalbanchan(small side dish) isgosari-namul(고사리나물), which consists of prepared fernbrake fiddleheads that have beensauteed.  It is also a component of the popular dishbibimbap,yukgaejang, andbindae-tteok. InJeju Island, southernmost island of South Korea, collecting it in April to May is a convention.
InJapan, bracken fiddleheads are a prized dish, and roasting the fiddleheads is reputed to neutralize any toxins in the vegetable. In Japan, fiddleheads of flowering fern (Osmunda japonica), known aszenmai(薇), as well as those of the ostrich fern (Matteuccia struthiopteris), known askogomi(コゴミ), are commonly eaten in springtime. Fiddleheads in Japan are consideredsansai, or wild vegetables. They are also traditionally used to makewarabimochi,a Japanese-style dessert.
In theIndian subcontinent, it is found in theHimalayanstates ofNorthandNortheast India. In the state ofTripura, it is known as muikhonchok in theKokboroklanguage. As part of theTripuri cuisine; fiddlehead fern is prepared by stir frying as bhaja served as a side dish. InManipurit is known as 'Chekoh' in the localThadoulanguage. It is usually eaten stir fried with chicken, eggs, prawns or other proteins.
In Mandi (Himachal Pradesh) it is called Lingad and used for vegetable pickling. In theKullu ValleyinHimachal Pradesh, it is known locally aslingriand is used to make a picklelingri ka achaar. In theKangra Valleyit is calledlungduin theKangri dialectand is eaten as a vegetable. InChambait is known as "kasrod". 
InKumaon divisionofUttarakhand, it is called limbra. InGarhwal divisionofUttarakhand, it is calledlangudaand eaten as a vegetable. InDarjeelingandSikkimregions, it is calledniyuro(नियुरो) and is common as a vegetable side dish, often mixed with local cheese and sometimes pickled. In Southern regions ofWest Bengalit is known as dheki shaak or dheki shaag.
InAssam, it is known asdhekia xak(Assamese:ঢেকীয়া শাক); there it is a popular side dish. In the area ofJammuinJammu and Kashmir, it's known askasrod(कसरोड). The most famousDogradish iskasrod ka achaar(fiddlehead fern pickle). InPoonch, it is known as 'Kandor'(कंडोर) in local language. InKishtwar, it is known asted(टेड‍‌) in the local languageKishtwari. It is also cooked as a dry vegetable side dish to be eaten withrotisorparathas. In Ramban district of Jammu and Kashmir, it is called "DheeD" in Khah language.
InNepal, it is aseasonal foodcalledniyuro(नियुरो) orniuro(निउरो). There are three varieties of fiddlehead most commonly found in Nepali cuisine, namely सेती निउरो having whitish green stem, काली निउरो having dark purple stem, and ठूलो निउरो having large green stems.  It is served as a vegetable side dish, often cooked in local clarified butter. It is also pickled.
Ostrich ferns (Matteuccia struthiopteris), known locally as "fiddleheads", grow wild in wet areas of northeastern North America in spring. TheMaliseet,Mi'kmaq, andPenobscotpeoples ofEastern CanadaandMainehave traditionally harvested fiddleheads, and the vegetable was introduced first to theAcadiansettlers in the early 18th century, and later toUnited Empire Loyalistsas they began settling inNew Brunswickin the 1780s.Fiddleheads remain a traditional dish in these regions, with most commercial harvesting occurring in New Brunswick,Quebecand Maine, and the vegetable is considered particularly emblematic of New Brunswick.North America's largest grower, packer and distributor of wild fiddleheads establishedOntario's first commercial fiddlehead farm inPort Colbornein 2006.Fiddlehead-producing areas are also located inNova Scotia,VermontandNew Hampshire.The Canadian village ofTide Head, New Brunswickbills itself as the "Fiddlehead Capital of the World."
Fiddleheads are sold fresh and frozen. Fresh fiddleheads are available in the market for only a few weeks in springtime, and are fairly expensive. Pickled and frozen fiddleheads, however, can be found in some shops year-round. The vegetable is typically steamed, boiled and/or sautéed before being eaten hot, withhollandaise sauce, butter, lemon, vinegar and/or garlic, or chilled in salad or withmayonnaise.
To cook fiddleheads, it is advisedto remove the brown papery husk before washing in several changes of cold water, then boil or steam them. Boiling reduces the bitterness and the content oftanninsand toxins. TheCenters for Disease Control and Preventionassociated a number of food-borne illness cases with fiddleheads in the early 1990s. Although they did not identify a toxin in the fiddleheads, the findings of that case suggest that fiddleheads should be cooked thoroughly before eating.The cooking time recommended by health authorities is 15 minutes if boiled and 10 to 12 minutes if steamed.The cooking method recommended by gourmets is to spread a thin layer in a steam basket and steam lightly, just until tender crisp.
Māoripeople have historically eaten young fern shoots calledpikopiko, which can refer to several species of New Zealand ferns.
Fiddleheads are low in sodium, but rich in potassium.
Many ferns also contain theenzymethiaminase, which breaks downthiamine. This can lead toberiberi, if consumed in extreme excess.
Further, there is some evidence that certain varieties of fiddleheads, e.g. bracken (Pteridiumgenus), are toxic.It is recommended to fully cook fiddleheads to destroy theshikimic acid.Ostrich fern (Matteuccia struthiopteris) is not thought to cause cancer,although there is evidence it contains a toxin unidentified as yet.