Tricholoma colossus (species of mushroom)
A large, edible mushroom species native to Japan. Typically used in culinary or mycological contexts.
Samatsu is a large mushroom found in pine forests in autumn.
In this region, they put samatsu in miso soup and eat it.
The name サマツ is likely a combination of 早 (sa, 'early') and 松 (matsu, 'pine'), referring to its early appearance in pine forests, but the exact derivation is uncertain.