 Amanita phalloides / æməˈnaɪtə fəˈlɔɪdiːz / , commonly known as the death cap , is a deadly poisonous basidiomycete fungus , one of many in the genus Amanita . Widely distributed across Europe , A. phalloides forms ectomycorrhizas with various broadleaved trees . In some cases , the death cap has been introduced to new regions with the cultivation of non @-@ native species of oak , chestnut , and pine . The large fruiting bodies ( mushrooms ) appear in summer and autumn ; the caps are generally greenish in colour , with a white stipe and gills . 
