Stropharia

The genus Stropharia (sometimes known by the common name roundheads) is a group of medium to large agarics with a distinct membranous ring on the stipe. Well-known members of this genus include the edible Stropharia rugosoannulata and the blue-green verdigris agarics (Stropharia aeruginosa and allies). Stropharia are not generally regarded as good to eat and there are doubts over the edibility of several species. However the species Stropharia rugosoannulata is regarded as prized and delicious when young and is now the premier mushroom for outdoor bed culture by mycophiles in temperate climates.

==Taxonomy== The scientific name is derived from the Greek 'στροφος/strophos' meaning "belt", in reference to the annulus present on the stipe. Spore print color is generally medium to dark purple-brown with a white edge at maturity, except for a few species that have rusty-brown spores. There is a great deal of variation, however, since this group as presently delimited is polyphyletic. Members of the core clade of Stropharia are characterized by crystalline acanthocytes among the hyphae of the mycelium that make up the rhizoids at the base of the mushroom, and in one species, Stropharia acanthocystis, also occur in the hymenium.