Summary:
Psilocybe baeocystis is most easily recognized by 1) its robust stature, and 2) its whitish cap when dry (strongly hygrophanous). Other features include 3) a hygrophanous cap that is dark chestnut brown to brownish orange or olive-brown, viscid, and striate, 4) flesh that stains blue when cut, 5) adnate to sinuate close gills that are grayish to dark cinnamon brown, becoming dark purplish gray with pallid edges, 6) a pallid to brownish stem that bruises or becomes blue-green, 7) a farinaceous odor and taste, 8) growth on decaying conifer wood or woody material, particularly on coniferous bark mulch in gardens and parks, and 9) microscopic characters including asymmetric subelliptic spores. Guzman says it may be synonymous with Psilocybe aztecorum.

Cap:
1.5-5.5cm across, conic with incurved margin, expanding to convex or (in extreme age) flat, margin distinctly wavy when convex; hygrophanous, dark olive-brown to buff-brown, (occasionally steel-blue), becoming copper brown in center when drying, fading to pallid white, easily bruising bluish and about margin often tinted greenish; viscid with usually separable cap skin, margin translucent striate, (Stamets), 1-2(5.4)cm across, conic when young to convex or bell-shaped when old, slightly flat or depressed in old specimens, sometimes slightly umbonate, margin incurved at first, markedly undulate or wavy; "strongly hygrophanous, dark chestnut brown, brownish vinaceous red, brownish orange or olive brown, but soon fading to yellowish, whitish or cream milk color from the top to the margin, readily staining blue or greenish blue, remaining in some specimens completely dark blue to dark brown olive"; viscid because of colorless gelatinous separable pellicle [cap skin], bald, even or slightly verrucose-venose at top to faintly striate at margin when moist, but not when very young, (Guzman(1))

Flesh:
yellowish brown in cap, brownish orange in stem, staining blue when cut, (Guzman(1))

Gills:
adnate to sinuate, close; grayish to dark cinnamon brown with edges remaining pallid, (Stamets), adnate to uncinate; "rose brown to brownish violaceous or dark cinnamon, sometimes somewhat mottled", with edges colored as faces or whitish, (Guzman(1)), attached, close, broad; grayish becoming dark purplish gray, (Lincoff)

Stem:
5-7cm x 0.2-0.3cm, equal to nearly equal, brittle, stuffed with loose fibers; pallid to brownish surface sometimes covered with fine whitish fibrils, while often more yellowish toward top; distinct rhizomorphs around stem base, (Stamets), 3-5.5(7)cm x (0.1)0.2-0.3(0.4)cm, equal, "straight or irregularly flexuous or twisted, stuffed with loose whitish to yellowish fibrils"; white to yellowish orange-brown when touched, readily staining blue-green when injured; "covered irregularly with floccose fibrils, sometimes scabrous-strigose at the base, ascending upwards, but without rhizomorphs", (Guzman(1))

Veil:
partial veil thinly cortinate becoming rapidly inconspicuous, (Stamets), white and arachnoid [cobwebby] or cortinate, "copious at first, but leaving fibrillose remnants on the stem", sometimes forming a subannular [almost ring-like] and very fleeting zone on upper stem, (Guzman(1))

Odor:
weakly to strongly farinaceous (Guzman(1))

Taste:
weakly to strongly farinaceous (Guzman(1))

Microscopic spores:
spores 10-12 x 6-7 microns, mango-shaped; basidia 4-spored; pleurocystidia absent, cheilocystidia 20-30(40) x 4.5-6(9) microns, fusoid with narrow neck, (Stamets), spores (8.5)9.5-13.7(17) x (5)5.5-6.6(7.1) x 6.6-7.1 microns, elongate-elliptic in face view, asymmetrically elliptic or mango-shaped in side view, thick-walled (1 micron), "dark yellowish brown, with a broad germ pore and a short basal appendage"; basidia 1-2-3- or mostly 4-spored, (20)22-31 x 6.3-8(9) microns, colorless or sometimes stramineous [straw-colored], "clavate or subcylindric or subpyriform"; pleurocystidia "present only near the edge of the gill, sometimes absent or similar to the cheilocystidia", cheilocystidia abundant, forming a sterile band, 20-32(44) x 4.4-6(9) microns, colorless, fusoid-ampullaceous with a long, thin neck 1-2 microns wide, simple or rarely irregularly bifurcate, sometimes with a colorless viscid drop at top; clamp connections very common, (Guzman(1)), spores (9)10-13(15) x (5)5.5-6.5(7) microns, thick-walled with wall up to 1 micron thick; pleurocystidia absent, cheilocystidia 19-33(40) x (5)6-8 microns, sublageniform, frequently and irregularly branched, (Guzman(4))

Spore deposit:
violet brown (Guzman(1)), dark purplish (Lincoff)

Notes:
It is known from BC, WA, and OR, (Guzman(1)).

EDIBILITY

hallucinogenic, 0.15-0.85% psilocybin, up to 0.59% psilocin, up to 0.10% baeocystin, losing considerable potency from drying or in damage, (Stamets)