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

Summary:
Features include small size, delicate consistency, pale colors when young, translucent pleated cap, failure to deliquesce, growth in crowded troops, black spore deposit, and (microscopically) cap surface with large pileocystidia. Coprinellus disseminatus was in Section Hemerobi of Coprinus sensu lato (with Parasola plicatilis) Subsection Setulosi according to Singer, and in Section Setulosi (with Coprinellus congregatus, Coprinellus ephemerus, Coprinellus hiascens and Coprinellus impatiens, characterized by pileocystidia) according to Moser, but some placed this non-deliquescent species in Pseudocoprinus. Coprinellus disseminatus is the more recently published name based on molecular evidence (Redhead(49)).

common throughout temperate North America in spring, summer and fall, (MI mentioned specifically), (Smith(15)), widely distributed in eastern North America and CA (Phillips), reported from BC (Roberts, C.), reported from WA by Andrew Parker, pers. comm., Europe (Moser)

Cap:
0.5-1cm across, "oval soon becoming bell-shaped, then sometimes convex"; pallid or buff with cinnamon brown to honey brown center, becoming grayish toward margin when old; deeply striate or pleated to center and translucent when mature, minutely scurfy when young, (Arora), 0.5-1(1.5)cm across, "obtusely conic to nearly convex when young", expanding to narrowly bell-shaped or obtusely conic; "white when young or the disc tinged pale buff to honey-color, gradually becoming gray or grayish brown except the disc which remains honey-color"; moist, at first pruinose to scurfy, becoming bald, prominently plicate-striate [pleated-striate] to the disc, (Smith)

Flesh:
very thin and soft (Arora), very thin and fragile, (Smith)

Gills:
"adnate to adnexed or appearing free, fairly well-spaced"; "at first white but soon gray, finally black or slightly paler; not deliquescing", (Arora), "ascending-adnate, subdistant, broad"; white at first becoming ash-gray and finally black, (Smith), "attached, nearly distant, broad; white then amber to black, but not inky or deliquescing", (Phillips), lilac-gray-brown, not deliquescing, (Moser)

Stem:
1.5-4cm x 0.1-0.2cm, thin, equal, hollow, fragile, often curved; white or buff; smooth, (Arora), 2-3cm x 0.05-0.1cm, hollow, very fragile; white; coated with minute hairs, becoming bald, base "hardly strigose", (Smith)

Veil:
partial veil absent (Arora)

Odor:
none (Phillips, Smith)

Taste:
mild (Smith)

Microscopic spores:
spores 7-10 x 4-5 microns, elliptic, smooth, with large apical germ pore, (Arora), spores 7-10(11) x 4-4.5 microns, subelliptic to ventricose-oval, apex truncate from colorless germ pore, dark purplish under microscope when fresh, dull chocolate revived in KOH; basidia 4-spored, trimorphic, the longest 28-32 x 5-7 microns, base slightly ventricose and elongated in upper [distal] part to a cylindric neck 4-5 microns in diameter, the shortest 18-20 x 7-8 microns and clavate; pleurocystidia none, cheilocystidia rare to scattered, clavate to saccate, 10-15 microns broad, occasionally fusoid-ventricose and similar to pileocystidia, paraphyses 10-12 x 8-11 microns; large pileocystidia 100-180 x 10-20 microns "with rounded apices and cylindric above a slightly ventricose base", "scattered over the surface and arising from among the cells of the palisade", the elongated necks of the pileocystidia 10-15 microns in diameter; caulocystidia more or less similar to pileocystidia and readily collapsing; clamp connections not seen, (Smith), cheilocystidia 60-80 x 8-20 microns, cylindric-bulbous, (Moser), pileocystidia large, 150-215 microns long (Hansen)

Spore deposit:
dark brown to black (Arora), blackish (Smith)