Summary:
Features include 1) a distinctly umbonate, viscid, peelable cap that is yellowish to pale ochraceous brown toward the disc, 2) a cap margin that is decorated with whitish veil remnants, 3) close, broad gills that are whitish then grayish then purplish brown, 4) a pallid to yellowish, slender stem that is powdery above the ring zone and initially finely fibrillose below the ring zone, 5) growth on dung, 6) a dark purplish brown spore deposit, and 7) large spores on 2-spored basidia. Stamets gives this species as a synonym of Psilocybe luteonitens (Peck) Sacc. The reason for the transfer to Psilocybe would be the lack of chrysocystidia. The online Species Fungorum, accessed June 25, 2012, included Stropharia luteonitens (Fr.) Quel. with Psilocybe luteonitens (Fr.) Park.-Rhodes as a synonym, but maintained Stropharia umbonatescens (Peck) Sacc. separately.

Cap:
1-4cm across, conic - bell-shaped with a distinct umbo, expanding to convex to broadly convex to nearly flat with or without an acute-to-low umbo; yellowish to pale ochraceous brown toward the disc; surface viscid when moist from a separable gelatinous pellicle, margin decorated with fragile, whitish partial veil remnants [the photograph in Stamets showing the whole marginal area whitish], (Stamets), whitish (Rinaldi)

Flesh:
thin; pallid

Gills:
adnate to subdecurrent [somewhat decurrent], close, broad; whitish at first then grayish, and eventually purplish brown

Stem:
3.5-7cm x 0.2-0.4cm, equal and slender; pallid to yellowish, lighter than the cap; surface powdered above the ring region, and initially covered with fine fibrils below, but often smooth when old

Veil:
partial veil white, thinly membranous, floccose, leaving an obscure evanescent [fleeting] ring zone of fibrils if at all

Microscopic spores:
spores 15-19 (22) x 10-11 microns, subelliptic [somewhat elliptic] to elliptic; basidia 2-spored, pleurocystidia absent, cheilocystidia 25-45 x 3-7 microns, cylindric to sublageniform with a flexuous [wavy], elongated apex

Spore deposit:
dark purplish brown

Notes:
Stropharia umbonatescens has been reported from WA, OR, ID, MI, NY, Mexico, Europe, and Asia, (Stamets). There is a collection from BC at the University of British Columbia.

EDIBILITY

unknown, activity unknown

Synonyms and Alternate Names:
Protostropharia umbonatescens (unpublished combination)
Psilocybe luteonitens (Peck) Sacc.