Lyophyllum shimeji; hon-shimeji mushroom
Refers specifically to the wild species Lyophyllum shimeji, a prized edible mushroom. Often called 本占地 (ほんしめじ) to distinguish it from cultivated varieties.
See also: ホンシメジ
Hon-shimeji has a good aroma and is treated as a high-class ingredient.
shimeji mushroom (cultivated); brown beech mushroom
In everyday usage, refers to cultivated mushrooms sold as 'shimeji' in supermarkets, typically Hypsizygus tessellatus (buna-shimeji) or similar. Not the same as the wild hon-shimeji.
See also: ヒラタケ
I bought shimeji mushrooms at the supermarket and put them in miso soup.
Buna-shimeji mushrooms are mild and easy to eat.