Summary:
Features include 1) a hygrophanous, dark reddish brown, viscid, peelable, striate cap, 2) crowded, adnate to adnexed gills that are pale cinnamon-buff then dark violaceous brown with whitish edges, 3) a slender stem that is reddish to blackish under appressed fibrillose whitish veil remnants in lower 2/3, 4) slight to farinaceous odor and taste, 5) growth in bogs or woodland close to bogs, 6) a deep purple brown spore deposit, and 7) microscopic characters. The online Species Fungorum, accessed April 18, 2016, gives the correct name of Psilocybe atrobrunnea sensu Guzman as Psilocybe turficola J. Favre, Bull. trimest. Soc. mycol. Fr. 35: 196 (1939).

Cap:
1.5-5cm across, conic - bell-shaped or convex; dark reddish brown, becoming blackish brown when old, pale tan when faded; smooth, viscid, margin striate when moist, (Phillips), 2-4(6)cm across, bluntly conic to convex or bell-shaped, usually umbonate, sometimes with sharp nipple, expanding to broadly convex when old, margin inrolled to incurved at first; strongly hygrophanous, dark reddish brown to blackish reddish brown then brown, fading to pale reddish brown; viscid when moist from thin but often separable cap skin, smooth, margin translucent-striate, and adorned with whitish veil remnants, (Stamets), (1)2-4(6)cm across, convex to bell-shaped, or umbonate, usually mammillate with short papilla, becoming more or less flat, margin inrolled at first without veil remnants, at least none conspicuous; hygrophanous, dark reddish brown at first, usually blackish reddish vinaceous or brown when old or when moist, "fading to brownish or pale reddish brown to ochraceous buff"; viscid with thin separable cap skin, bald but when young faintly white-fibrillose from remnants of rudimentary veil, margin somewhat striate when moist, (Guzman)

Flesh:
thin; pallid, (Phillips), pliant in cap and fairly tough in stem; "dark brown and watery at first, fading to cinnamon buff", (Guzman)

Gills:
"adnate, crowded, broad; pale cinnamon buff, then dark violaceous brown when mature", (Phillips), adnate to adnexed; dull cinnamon brown to dark purplish brown when mature, (Stamets), adnate or adnexed; pallid cinnamon brown when young to dark purplish brown or violaceous brown when old, with white edges; edges fimbriate [fringed], (Guzman)

Stem:
6-12cm x 0.2-0.4cm, equal, flexuous [wavy], fibrous; covered with pale fibrils but becoming darker brown from base up when old, (Phillips), 8-18cm x 0.3-0.5(0.6)cm, equal, but swelling toward base, tough, flexuous; reddish to blackish underneath appressed fibrillose whitish remnants in lower 2/3, pruinose in upper part, base with whitish mycelium, (Stamets), 8-18cm x (0.25)0.4-0.5(0.6)cm, equal and flexuous, or subbulbous or subpyriform at base, cartilaginous, tough, stuffed but soon hollow; at first covered with appressed white fibrils, "pale reddish brown with zones, more reddish or blackish and white from the veil fibrils", pruinose at top, (Guzman)

Veil:
"more or less developed in young stages as white fibrils", fleeting except for fibrils on stem, no ring, (Guzman)

Odor:
slight, mealy, (Phillips), faint (Guzman)

Taste:
mealy (Phillips), slightly fungoid or none (Guzman)

Microscopic spores:
spores 9-12.5 x 5-7 microns, elliptic, smooth, (Phillips), spores 9-12(14) x 5-7(9) microns, elliptic; basidia 4-spored; pleurocystidia absent or close to gill edge and then similar to cheilocystidia, 30-38 x 4-6(8) microns, cheilocystidia 18-30(36) x 4-7 microns, "lageniform or fusoid-ventricose with an extended neck", (Stamets), spores (8)9-12(14) (15!) x 5-7(9) x 5-6.6 microns, elliptic, thick-walled (0.7-1.5 microns thick), yellowish brown, with a flat somewhat narrow germ pore; basidia 4-spored, 22-30 x 7-8.8 microns, colorless, subventricose or subpyriform; pleurocystidia absent or scarce or inconspicuous, somewhat embedded in hymenium, 30-38 x 4-6(8) microns, similar to cheilocystidia, cheilocystidia abundant, forming a sterile band, 18-30 (36) x 4-7 microns, colorless, "lageniform or fusoid-ventricose with a long neck", 1.5-2.5 microns wide, forming a sterile band, in old specimens cheilocystidia may be branched; clamp connections present, (Guzman)

Spore deposit:
deep purple brown (Phillips), dark violaceous brown (Stamets), dark brown violaceous (Guzman)

Notes:
Psilocybe atrobrunnea has been found at least in BC, MI, NY, ME, Czech Republic, Slovakia, Finland, France, Germany, Norway, Sweden, Poland, and the United Kingdom, (Stamets).

EDIBILITY

no, (Phillips), possibly active: one report of psilocybin, (Stamets)

Synonyms and Alternate Names:
Psilocybe turficola J. Favre