 Use of this mushroom as a food source also seems to have existed in North America . A classic description of this use of A. muscaria by an African @-@ American mushroom seller in Washington , D.C. , in the late 19th century is described by American botanist Frederick Vernon <unk> . In this case , the mushroom , after <unk> , and <unk> in vinegar , is made into a mushroom sauce for <unk> . It is also consumed as a food in parts of Japan . The most well @-@ known current use as an edible mushroom is in <unk> Prefecture , Japan . There , it is primarily salted and <unk> . 
