Gymnopilus junonius
Gymnopilus junonius is a species of mushroom in the family Cortinariaceae. Commonly known as the spectacular rustgill, this large orange mushroom is typically found growing on tree stumps, logs, or tree bases. Some subspecies of this mushroom contain the neurotoxic oligoisoprenoid gymnopilin. Taxonomy. This species was formerly known as Gymnopilus spectabilis, or Pholiota spectabilis v. junonia (Fr.) J.E Lange. The 'Gymn' in the present nomen means 'naked', and 'Juno' was the wife of Jupiter. Description. The cap ranges from across, is convex to flat, and is bright yellow-orange in younger specimens and orange/brown or reddish brown  in older ones, with a dry scaly surface. The flesh is yellow, the odor mild and taste bitter. The stem is long, 1–5 cm thick, and often narrows near the base. The frail ring is dusted with rusty orange spores, and the gill attachment to the stem is adnate to sub-decurrent. It stains red with KOH and turns green when cooked in a pan. The spore print is rusty orange. Unlike psychoactive relatives in the "Psilocybe" genus, it typically does not bruise blue, but smaller specimens, or "aborts" of related active species, occasionally exhibit bruising. This mushroom usually grows  in clusters from several to several dozen individuals, but sometimes grows solitary. The mushroom is inedible due to its bitter taste. Gymnopilus junonius lacks psilocybin and does not stain blue, however some similar looking related species are hallucinogenic. Similar species. This mushroom is often mistaken for "Gymnopilus ventricosus", which also contains no psilocybin and Gymnopilus luteus and Gymnopilus subspectabilis, which do. It also resembles "Armillaria mellea" and "Omphalotus olivascens". Distribution and habitat. "Gymnopilus junonius" is found in Europe, Australasia and South America. It grows in dense clusters on stumps and logs of hardwoods and conifers. This mushroom is most common  in moist, lowland wooded areas near rivers. This species does not occur in North America - however some similar looking species do, including Gymnopilus ventricosus on the west coast and Gymnopilus luteus and Gymnopilus subspectabilis in the midwest and east. Biochemistry. This mushroom contains bis-noryangonin and hispidin, which are structurally related to alpha-pyrones found in kava. Japanese researchers have found oligoisoprenoids, or neurotoxins in this mushroom.