About Hypsizygus marmoreus (Peck) H.E.Bigelow
Hypsizygus marmoreus (Peck) H.E.Bigelow has a white to yellow cap that measures 5–15 centimetres (2–6 in) across, starting convex before becoming flat and sunken. Its gills are adnexed to sinuate, fairly closely spaced, and change from whitish to cream as it matures. The stem grows up to 11 cm (4+1⁄4 in) long and 3 cm (1+1⁄8 in) wide, and is wider at the base. The firm, white flesh has a pungent scent and a mild taste, and the spore print is white to buff.
This species is native to East Asia and common in northern North America. It grows singly or in scattered groups on hardwood, often far above the ground. It frequently grows on beech trees, which gives it its common name.
It is cultivated locally in temperate climates across Europe, North America, and Australia, and sold fresh in supermarkets. Two commercial cultivars originate from Japan: Buna-shimeji (ja:ブナシメジ) is the wild-type brown form, known by common names including brown beech mushroom, beech mushroom, and brown clamshell mushroom. Bunapi-shimeji (ja:ブナピー) is a white UV-induced mutant of Buna-shimeji, sold as white beech mushroom or white clamshell mushroom. The original strain is registered by Hokto Corporation.
This mushroom is edible but tough and bitter when raw, so it requires cooking; cooking eliminates the bitter taste and makes the mushroom easier to digest. Cooked Hypsizygus marmoreus has a firm, slightly crunchy texture and a nutty flavor. It is commonly added to stir-fried dishes including wild game and seafood, and is also used in soups, stews, and sauces. When prepared on its own, whole shimeji mushrooms (with only the very end of the stem trimmed off) can be sautéed over high heat, or slow roasted on low heat with a small amount of butter or cooking oil. Shimeji is also used in soups, nabe, and takikomi gohan.
