Mushrooms are members of the fungus family. They grow on decaying material and are reproduced from spores. Mushrooms have grown wild since ancient times, surviving wherever there is decaying material to support their growth. There are thousands of mushrooom species varying by color, shape, size and flavor. The cultivated button mushroom is the most common variety found in supermarkets. Several varieties of wild mushrooms have become popular in recent years. Some of these varieties are now cultivated. Pennsylvania produces half of the United States mushroom crop. Mushrooms are cultivated in special windowless buildings where temperature, humidity and ventilation are controlled.

There are many varieties of fresh mushrooms available in supermarkets and specialty markets in the United States.

Button (or Field) Mushrooms are the most common mushrooms grown and sold. They are plump and dome-shaped with a smooth texture and mild flavor. The color of button mushrooms varies from white to pale tan.

Chanterelle mushrooms, which are yellowish-orange in color, grow wild in Pacific Northwest forests and in Europe. They have a flared trumpetlike shape, delicate flavor and fruity fragrance. Chanterelles are available fresh, but in limited supply, in the late spring. They are more commonly available dried.

Enoki are Japanese mushrooms that are now cultivated in California. They have long, thin stems with tiny caps. They are creamy white in color with a delicate, slightly fruity flavor. Enoki mushrooms are very perishable and should be used within two or three days. Unlike other mushrooms they do not require cleaning, but any mass at the base of the stems should be removed. They are best eaten fresh.

Morels are wild mushrooms that are difficult to cultivate. They have an elongated spongelike dome and a rich, intense earthy flavor. Look for them in the spring.

Oyster mushrooms are wild mushrooms from Asia that are now cultivated in the United States. They have a broad shell shape. Oyster mushrooms are creamy white to pale brown in color with a strong peppery flavor when raw but a milder cooked flavor. They are very perishable and should be used within two or three days.

Portobello mushrooms have large pancake-shaped dark brown caps on thick tough stems. They have a firm texture when cooked and a beeflike flavor. Because of their large size and sturdiness, they are a good choice for grilling. They are sometimes substituted for beef in vegetarian sandwiches, stir-fries and fajitas.

Shiitake are wild mushrooms from Japan that are easily cultivated. They have brown caps, a firm texture and thin tough stems, which are usually trimmed away. Their woodsy odor and rich, smoky mushroom flavor contribute to their popularity.

Straw mushrooms, an Asian variety with a deep umbrella-shaped cap, are more commonly seen canned than fresh. Look for fresh straw mushrooms at Asian markets. They have a mild flavor.

The following dried mushrooms are usually available in large supermarkets and specialty markets:

Chanterelle mushrooms are yellow-orange in color and have a flared, hornlike shape.

Porcini mushrooms (also known as cèpes) are tan to pale brown in color. They have a pungent, woodsy flavor.

Wood ears (also known as cloud ears and tree ears) are popular in Asian cuisines. They are available in Asian markets and large supermarkets.

Button mushrooms are available all year but the peak season is fall and winter. They are sold in 8- and 16-ounce packages and in bulk. Cultivated wild mushrooms are generally available all year. Morels and chanterelles, which are not cultivated, can be found in large supermarkets in the late spring. Button mushrooms are also available canned.

Mushrooms should be firm and evenly colored with tightly closed caps. Avoid ones that are slimy or have any soft dark spots.

1 pound fresh mushrooms = 6 cups slices; 2 cups cooked slices.

1 (4-ounce) can sliced mushrooms = 2/3 cup.

Fresh mushrooms with the exception of enoki and oyster mushrooms will keep for five to seven days in the refrigerator. Enoki and oyster mushrooms should be used within two or three days. Wrap in paper towels and refrigerate unwashed in a plastic bag. Dried mushrooms should be stored in a cool, dry place for up to six months.

Wipe mushrooms with a damp paper towel, brush with a mushroom brush or soft toothbrush, or rinse briefly under cold running water to remove the dirt. (Do not wash enoki mushrooms.) Pat dry before using. Never soak in water because they absorb water and will become mushy. Trim and discard stem ends. (Shiitake and portobello mushrooms have tough stems that should be discarded.) Slice mushrooms through their stems or chop.

To reconstitute dried mushrooms, soak them in warm water until softened, about 20 to 30 minutes or in boiling water for 15 to 20 minutes. Drain off the soaking liquid and save it for use in soups and stews. Swish reconstituted dried mushrooms in a bowl of fresh warm water to remove any embedded dirt. Drain mushrooms on paper towels.