Cap: .8-2.5 cm broad. Obtusely conic to campanulate with an acute umbo. Tawny dark brown when moist, fading to a pale yellow-brown. Smooth, viscid when moist with a thin gelatinous pellicle.
Gills: Adnate to adnexed. Close to subdistant and narrow to moderately broad. Dull grayish brown to cinnamon or smoky brown with age. Edges white.
Stem: 20-80 mm long x 1-3 mm thick. Equal to slightly enlarge at the base. Brittle.
Spores: 6-9.5 x 4-5.5 µ.
Sporeprint: Dark purplish brown.
Habitat: Gregarious but not cespitose on wood debris, wood chips (preferably alder), or even decayed conifer substratum.
Distribution: From west of the Cascades in southern Oregon to British Columbia, Canada. Also reported from Idaho and as far away as Finland.
Season: From late September through December.
Comments: Very similar to Psilocybe pelliculosa and is usually found growing along with them. Stamets (1996) reports that in some colonies of Psilocybe silvatica the caps were more yellow in appearance than those of the caps of Psilocybe pelliculosa.
Dosage: Moderately weaker than Psilocybe semilanceata. From 20 to 40 fresh mushrooms, 1/3 of a fresh ounce or from 2 to 4 grams dried.