Psilocybe liniformans var. americana, is a psilocybin mushroom

Psilocybin mushroom

Psilocybin mushrooms are fungi that contain the psychoactive compounds psilocybin and psilocin. There are multiple colloquial terms for psilocybin mushrooms, the most common being shrooms or magic mushrooms....

 of the Agaricales

Agaricales

The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...

 family, in the section Semilanceatae, having psilocybin

Psilocybin

Psilocybin is a naturally occurring psychedelic prodrug, with mind-altering effects similar to those of LSD and mescaline, after it is converted to psilocin. The effects can include altered thinking processes, perceptual distortions, an altered sense of time, and spiritual experiences, as well as...

 as its main active compound.

Description

• The cap is 1 — 2.5 cm convex to nearly plane, and is sometimes broadly umbonate but not papillate. It is smooth, dull grayish brown to slightly olivacous, more reddish at the center, hygrophanous
  Hygrophanous
  The adjective hygrophanous refers to the color change of mushroom tissue as it loses or absorbs water, which causes the pileipellis to become more transparent when wet and opaque when dry....
  
  , and becoming straw brown when dry with the center remaining more brownish. It sometimes has a bluish green tone, or olivacous tones at the margin when young.
• The gills are adnexed, subdistant, broad, and dark chocolate brown to purplish brown with age.
• The spores are dark purple brown, ellipsoid, and 13 — 14.5 by 7.5 — 8.8(10)µm.
• The stipe is 1.4 — 3.0 cm by 1 – 2 mm, equal, enlarging at the base. It is whitish to very pale brownish, darker below, bruising blue, and finely fibrillose in the lower portion. The partial veil is thin and soon disappears.
• The taste is weak to somewhat farinaceous; The odor is strongly aromatic to farinaceous.
• Microscopic features: The basidia
  Basidium
  thumb|right|500px|Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins.A basidium is a microscopic, spore-producing structure found on the hymenophore of fruiting bodies of basidiomycete fungi. The presence of basidia is one of the main...
  
   are 4-spored and pleurocystidia are absent. The cheilocystidia are 22 — 33 by 5.5 — 9 µm, lageniform and have an extended neck.

Habitat and formation

Psilocybe liniformans var. americana is found scattered to gregarious in rich pastures or grasslands, fruiting from summer to early winter. It has been collected in Washington, Oregon

Oregon

Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

, and Michigan

Michigan

Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

, and has also been reported from Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

 where it fruits in the spring.
This mushroom is very close to the type variety; the main difference is the lack of a gelatinous layer on the edge of the lamellae and the terricolous habitat.