May 12 2020
Marvel for a moment at a fiddlehead, the new frond of a fern. It stands like a watch spring coiled and ready to unwind, its smooth spiral shape contrasting sharply with the amorphous irregularity of its surroundings. It coils inward on itself until it ends with the tender young growing tip protected in the center of the spiral. So elegant is this spiral, so exquisite is its shape, that the fiddlehead has become firmly associated with ferns in the minds of most people.
In the northeastern United States, the best-known fiddleheads are those of the ostrich fern, Matteuccia struthiopteris. These are edible and offered for sale in reputable food markets from May through June. To cook them, they are first boiled in water for a few minutes to remove bitter-tasting tannins and then sautéed in butter. Of course, anything would taste good sautéed in butter, but most people also season ostrich fern fiddleheads with salt and pepper or dip them in hollandaise sauce. Fiddleheads have a texture resembling that of asparagus, but they have a flavor of their own, one hard to describe.
Worldwide, the fiddleheads of other fern species are also eaten. In many parts of tropical America, fiddleheads of the bramble fern (Hypolepis spp.) are consumed, and in eastern Asia, those of the twin-sorus fern (Diplazium esculentum) are sought-after. In many countries throughout the world, the fiddleheads of bracken (Pteridium spp.) are eaten. These appear long and lanky, quite different from the tightly coiled form of other fiddleheads. Bracken fiddleheads are commonly sold in Asian food stores, where they are often packaged in clear plastic bags containing a brown sauce. Eating bracken over a long time is not recommended because it has been associated with high incidence of stomach cancer.
Many fiddleheads bear an unusual feature: two pale lines on either side of the leaf stalk, called aerophores. They consist of specialized tissue through which the air diffuses into the young developing leaves. On their surface, they bear abundant stomata—the tiny “breathing pores” of the plant. Carbon dioxide is needed by the plant for photosynthesis, but what is most needed by young developing leaves whose cells are actively dividing, elongating, and differentiating is oxygen. These processes require energy made from oxygen through aerobic respiration. Next time you find a fiddlehead, look for these structures. Fiddleheads are easy to find at the New York Botanical Garden, especially at the Azalea Garden, the Native Plant Garden, and the Enid A. Haupt Conservatory.
