The name of this species refers to the fibrils on the Stipe (mycology) that turn bluish in age, or when handled.

Psilocybe cyanofibrillosa spores are purplish brown in deposit, subellipsoid in shape, and (9)9.5–11(12) x (5.5)6–6.6(7) μm.

The stipe is striate, pallid to yellow brown with fine fibrils that stain blue when handled.

Psilocybe cyanofibrillosa is found growing scattered to gregarious, from September to December from Northern California to British Columbia, Canada.

It is found in soils enriched with deciduous wood debris, among bush lupines, in Alder and Willow wood chips and bark mulch, Fir sawdust, in coastal regions, in rhododendron gardens and nurseries, and in flood plains in river estuaries.