Never eat a wild mushroom identified only from a website, a book or an app. Have every find checked in person by an expert, such as a mycological society.
Identification
Pholiota microspora forms clusters of small, rounded to flattened caps, 1–8 cm across, orange-brown, amber or butterscotch in color and coated with a thick, clear gelatinous layer that makes them glossy and slippery. Cultivated nameko is usually harvested very young, when the caps are only 1–2 cm wide and still closed. The gills are pale yellowish at first, becoming rusty brown as the spores mature. A slimy partial veil covers the young gills and leaves a gelatinous zone on the stem.
The spore print is brown to rusty brown; the spores are smooth and, as the name says, small for the genus. The species has long been called Pholiota nameko, a name still widely used in the trade and older literature.
Habitat and ecology
Nameko is a saprotroph that decays dead hardwood, especially beech and oak, in the forests of Japan, China and Taiwan, fruiting in fall in cool, humid weather. It does not grow wild in Europe, where similar-looking Pholiota species and other clustered brown mushrooms on wood are common.
Uses and importance
Nameko is a classic ingredient of Japanese cooking, especially in miso soup, with soba noodles, in hot pots and as a topping with grated radish. The slime thickens soups slightly and gives a smooth mouthfeel that is appreciated in Japanese cuisine; the taste is mild, slightly nutty and earthy. It is sold fresh in small packs and also canned or vacuum-packed.
Cultivation
Commercial nameko is grown on sterilized hardwood sawdust supplemented with rice or wheat bran in bags or bottles, while traditional and outdoor cultivation uses inoculated hardwood logs or stumps, often beech. Spawn run takes place at about 20–25 °C (68–77 °F); fruiting needs cool temperatures of roughly 10–16 °C (50–61 °F), very high humidity and fresh air. Cold-weather strains suit unheated sheds and outdoor beds in temperate climates. Harvest when the caps are still small and closed. Moderate difficulty: sterile technique is needed for sawdust blocks, while logs are simpler but slower.
Safety and edibility
Nameko is edible when correctly identified and cooked; do not eat it raw. Cultivated nameko from a reliable source is safe.
Wild brown mushrooms in clusters on wood are among the most dangerous groups for foragers. Never eat a wild mushroom based on a website or a photo: identification must be confirmed in person by an expert such as a mycological society or trained mushroom adviser. The deadly Galerina marginata, which contains amatoxins, grows in similar clusters on wood and has a similar brown spore print; amatoxin poisoning causes delayed symptoms and severe liver damage.
If you suspect mushroom poisoning, call Poison Help at 1-800-222-1222 or 911 in an emergency straight away, even before symptoms appear, and keep the remains of the mushrooms.
Look-alikes
Galerina marginata is not slimy, has a thin membranous ring and fine silvery fibers on the stem below it; it is deadly. Kuehneromyces mutabilis, the sheathed woodtuft, is edible but has a scaly stem below the ring and a two-tone, water-soaked cap, and is itself easily confused with Galerina. European Pholiota species such as Pholiota squarrosa are scaly, and some cause digestive upset.
In the United States
Nameko is grown by some US specialty growers and sold fresh or canned in Asian groceries.
Wild Pholiota species are common on wood in North America, but they are not reliable edibles, and deadly Galerina grows in similar places. Only eat nameko from a known cultivated source. Its slippery, gelatinous caps are prized in miso soup and noodle dishes.
