Summary:
Features include 1) small size, 2) a smooth sharply conic cap that is at least slightly viscid, and is hygrophanous, chestnut-brown to brown or olive-brown, fading to tan, olive-buff, or yellowish as it dries, 3) adnate to adnexed, close to crowded, narrow, pallid to gray gills that become dark purple-brown with whitish edges, 4) a stem that is whitish or with a brownish base, sometimes with a bluish or blue-green tinge when old, 5) flesh and stem that bruise blue only slightly if at all, 6) growth in tall grass, and 7) a dark purple-brown spore deposit. Psilocybe semilanceata rarely bruises bluish because it is high in psilocybin rather than psilocin (Stamets).

Cap:
0.5-2.5cm broad and high, narrowly conic to bell-shaped with a pointed umbo, scarcely expanding when old; chestnut brown to brown or olive-brown, fading to tan, olive-buff, or yellowish as it dries, "sometimes with bluish or olive stains"; "at least slightly viscid when moist", (Arora), (0.05)1-2(4)cm across, 0.05-2.5cm high, "frequently semi-spear shaped, first conic to obtusely conic or sharply conic", sometimes bell-shaped or umbonate or more often with distinct tall papilla, remaining so or becoming somewhat expanded, but retaining acute papilla; "hygrophanous, reddish brown at first to grayish brown, fading to pale ochraceous or yellowish brown or clay color, sometimes tinge of olive or greenish"; "viscid, with a removable gelatinous pellicle (only in fresh condition)", bald, but in young stages with the margin covered by white veil fibrils, "even but translucent-striate when moist, opaque when faded", (Guzman(1)), 0.5-2.5cm across, conic to obtusely conic to bell-shaped with an acute umbo, margin incurved and sometimes wavy when young; very hygrophanous, usually dark chestnut when moist drying to light tan or yellow, occasionally with an olive tint; viscid when moist from separable gelatinous pellicle, margin translucent-striate, (Stamets)

Flesh:
very thin; pallid, (Arora), very thin, pliant; whitish to colored as cap surface, in stem yellowish and somewhat pliant; slightly blueing, (Guzman(1))

Gills:
"adnate to adnexed or seceding"; pallid, soon becoming gray, finally dark purple-brown or chocolate brown, edges whitish, (Arora), adnate or adnexed; "pale grayish violaceous or dark violaceous brown", "concolorous or somewhat mottled, and with whitish somewhat fimbriate edges", (Guzman(1)), close, broad, (Lincoff), adnate, crowded, narrow; gray then brown, (Phillips), mostly adnexed, close to crowded, narrow; pallid rapidly becoming brownish and finally purplish brown with pallid edges, (Stamets)

Stem:
3-10cm x 0.1-0.2(0.3)cm, "equal, often curved or sinuous, pliant"; "whitish or with brownish base", sometimes with a bluish or greenish tinge when old, especially at base, (Arora), (4)5-11.3(11.9)cm x 0.1-0.2(0.3)cm, equal or somewhat subbulbous, cartilaginous, pliant, sometimes hollow but at first solid to stuffed with white pith; white or whitish to yellowish, but reddish brown downwards to cap-colored, often staining blue or greenish blue at base; smooth but pruinose at top, or slightly covered by fibrils but becoming bald when mature, (Guzman(1)), 4-10cm x 0.075-0.2(0.3)cm, equal, flexuous [wavy], pliant, stuffed with fibrous pith; pallid to more brownish toward base, attached mycelium may become bluish tinged, especially during drying, (Stamets), often bluish or greenish at the base when injured, (Ammirati)

Veil:
absent or rudimentary (Arora), arachnoid [cobwebby] or cortinate, "white and conspicuous in young stages, but soon evanescent, not forming an annulus in the mature stages", (Guzman(1)), partial veil thinly cortinate, "leaving an obscure evanescent annular zone of fibrils, usually darkened by spores", (Stamets)

Odor:
slightly farinaceous (Guzman(1), Siegel(2)), not distinctive (Phillips), mild to unpleasant (Miller)

Taste:
slightly farinaceous (Guzman(1)), slightly unpleasant, grassy, (Phillips), mild (Miller)

Microscopic spores:
spores 11-14 x 7-9 microns, elliptic, smooth; chrysocystidia absent on gills, (Arora), spores (11)12-14(18) x (6)7-8(9) x 4.8-5.4 microns, subelliptic or elliptic both in face and side view, sometimes slightly lemon-shaped, distinct broad germ pore up to 1.5 microns wide, thick wall (up to 0.5 microns), pale yellowish brown; basidia 4-spored, rarely 2-spored, 22-33 x 8-9.6 microns, colorless, "ventricose or subclavate, with a slight median constriction", sterigmata 2.4-3.6 microns long; pleurocystidia absent or scarce, when present similar to cheilocystidia, cheilocystidia abundant, forming a sterile band, 18-32(35) x (4.5)5-8 microns, colorless, "thin-walled, lageniform or bottle-shaped with a central or somewhat eccentric, elongate and flexuous neck" (1.5)2-3 microns wide, "frequently irregularly bifurcate or strong branched (mostly in older specimens)", sometimes with transparent, subgelatinous, viscous drop at apex, up to 60 microns in diameter; clamp connections very common, (Guzman(1)), spores 12-14 x 7-8 microns, elliptic; basidia 4-spored; pleurocystidia few to absent; cheilocystidia 18-35 x 4.5-8 microns, "lageniform with an extended and flexuous neck, often forked", (Stamets)

Spore deposit:
purple-brown (Arora), "dark violet brown or brown purplish darker" (Guzman(1)), dark purplish brown (Stamets)

Notes:
Guzman examined collections from BC, WA, OR, NY, Chile, Austria, Belgium, Czechoslovakia, Denmark, Finland, France, Germany, Italy, Netherlands, Norway, Sweden, United Kingdom (England), USSR, and Australia, (Guzman(1)). It has been reported also from CA, NB, NL, NS, PE, (Redhead), QC (Guzman(4)), and India, South Africa, and New Zealand, (Stamets).

EDIBILITY

hallucinogenic, not as potent as P. cyanescens but much stronger than P. pelliculosa, (Arora), 0.2-2.4% psilocybin, no psilocin, 0.2-0.36% baeocystin, important to distinguish from poisonous Galerinas, (Stamets), hallucinogenic and widely collected for this purpose, "but should be regarded as mildly poisonous; also, there is the possibility of misidentification", (Phillips)

Synonyms and Alternate Names:
Panaeolus semilanceatus (Fr.) J.E. Lange