Agaricus abruptibulbus

About

Agaricus abruptibulbus is a species of fungus in the genus Agaricus. It is commonly known as the abruptly-bulbous agaricus or the flat-bulb mushroom. First described by mycologist Charles Horton Peck, the mushroom is medium-sized, with a white, yellow-staining cap on a slender stipe which is bulbous on the base. The species smells slightly of anise and turns yellow when bruised or cut.

Summary from Wikipedia