E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include small size, an ochraceous brownish cap that becomes gray, deliquescing gills, downy white stem, growth in clumps, and (microscopically) pleurocystidia and pileocystidia. Coprinellus congregatus was in Section Setulosi of Coprinus sensu lato along with Coprinellus disseminatus, Coprinellus ephemerus, Coprinellus hiascens, and Coprinellus impatiens according to Moser. There are probably others in this section which has not been fully studied in the Pacific Northwest. The description here is derived from Moser(1).

Coprinellus congregatus was reported from BC by Lowe 1969 and Anastasiou 1967, according to Redhead(5).

Cap:
0.2-3cm high, fairly thin, then conic - bell-shaped; clay-colored, ochraceous-brownish, then gray, cap center leather pallid; at first lightly downy

Gills:
"young whitish to brown, edges white", deliquesces quickly (presumably becoming black)

Stem:
2-8cm x 0.06-0.3cm, white, downy, sometimes rooting to some extent

Microscopic spores:
spores 9-14.7 x 5.4-7.6 microns; basidia 4-spored; pleurocystidia 70-120 x 20-50 microns, cheilocystidia shorter; pileocystidia 50-110 x 7.5-17 x 4.5-12 microns