About Cortinarius smithii Ammirati, Niskanen & Liimat.
Cortinarius smithii Ammirati, Niskanen & Liimat., commonly called the western red dye mushroom, is an agaric fungus that belongs to the genus Cortinarius. In 1939, American mycologist Alexander H. Smith originally classified this fungus as Cortinarius phoeniceus var. occidentalis. In 2012, the species was renamed to honor Smith, after molecular analysis showed it was genetically distinct from Cortinarius phoeniceus. This fungus is found in North America. It is highly valued as a source of natural dye. The 2016 publication Mushrooms of the Redwood Coast calls it the "holy grail of California dye mushrooms"; it produces red dye when used with a neutral pH around 7 and an alum mordant, and orange dye at a pH of 4.
