Amanita virosa, commonly known in Europe as the destroying angel or the European destroying angel amanita, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe, A. virosa associates with various deciduous and coniferous trees. The large fruiting bodies (i.e., the mushrooms) appear in summer and autumn; the caps, stipes and gills are all white in colour. Immature specimens of A. virosa resemble several edible species commonly consumed by humans, increasing the risk of accidental poisoning. Small specimens may resemble the common Portobello mushroom to non-experts, but just one cap of A. virosa is enough to kill an adult human. The symptoms of poisoning generally come several hours afterwards, a fact which makes this fungus even more problematic. Along with its geographical namesakes, A. virosa is one of the most poisonous of all known poisonous mushrooms; its principal toxic constituent α-Amanitin damages the liver and kidneys, usually fatally. Taxonomy and naming The common name of destroying angel is applied to several all-white species of poisonous Amanita, to this species in Europe and to Amanita bisporigera in eastern North America, and A. ocreata in the west. A. virosa was first collected and described by Elias Magnus Fries in Sweden. Its specific epithet virosa derived from the Latin adjective virōsus 'toxic' (compare virus). Amanita virosa is very similar to several other species of all-white amanitas known as destroying angels, which has led to confusion over which occurs where. This specific name has been applied to all-white destroying angels occurring in North America, though others propose these all belong to Amanita bisporigera and other rarer species instead. There has been some question over whether Amanita verna is a valid species. Description Amanita virosa first appears as a white egg-shaped object covered with a universal veil. As it grows, the mushroom breaks free, though there may be ragged patches of veil at the cap edges. The cap is initially conical with inturned edges, before becoming hemispherical and flattening with a diameter up to . The cap often has a distinctive boss; it is able to be peeled and white, though the centre may be ivory in colour. The crowded free gills are white, as is the stipe and volva. The thin stipe is up to tall, with a hanging grooved ring. The spore print is white and the spores egg-shaped conical and 7–10 μm long. They stain blue