Guzmán, F. Tapia & Nieves-Riv.
- Cap: 1-3 cm diameter, at first subconical to campanulate, expanding to plano-convex with an umbo. Cap surface dark violet brown, translucent-striate near the margin, hygrophanous, fading to tan as it dries. Staining blue-green to black where bruised.
- Gills: Cream color when young, violet brown or chocolate brown in age, with adnexed attachment.
- Spores: Dark violet brown, subrhomboid in face view, subellipsoid in side view, thick walled, 6 x 5 um.
- Stipe: Central, equal with subbulbous base, hollow and cylindric, 3 to 8 cm long, 1 to 2 mm thick. Whitish to brown, ornamented with small flattened scales towards the base. The base is covered in tiny yellow fibers which help distinguish this from similar species. Staining blue-green to black where bruised.
- Taste: Farinaceous, sometimes with a slight mustard taste.
- Odor: Farinaceous, sometimes with a slight mustard odor.
- Microscopic features: Pigmented cheilocystidia and pleurocystidia present. Basidia four spored. Clamp connections common.
Distribution and habitat
Grows gregariously in groups, often on disturbed bare clay or moss. Found along hiking trails, in coffee plantations, tropical and subtropical forests, especially in landslide areas. Known only from Puerto Rico and Dominican Republic. 
- A new species of Psilocybe in the Caribbean with an emendation of Psilocybe guilartensis. Mycologia, 95(6), 2003, pp. 1171–1180. By Gaston Guzman, Fidel Tapia and Florencia Ramirez-Guillen