Haasiella

Haasiella is a fungal genus in the family Hygrophoraceae. It is a monotypic genus that contains only the species Haasiella venustissima. Haasiella splendidissima, formerly considered to be a distinct species based on its 4-spored basidia, was found by a DNA study to be synonymous with Haasiella venustissima. Haasiella venustissima is only known from Europe and is saprotrophic on wood. Haasiella was described as a new genus in 1966 by Czech mycologists František Kotlaba and Zdeněk Pouzar. It is most closely related to the genus Hygrophorus.

The genus name is in honour of Hans Haas, a German mycologist, who was a specialist on Agaricus from Schnait near Stuttgart.