Summary:
Coprinopsis nivea is characterized by the very large spores which are limoniform in face view and elliptic in side view, borne on 4-spored basidia, (Ulje), other features include its snow-white color due to a farinose-powdery veil (composed of spherocysts) that can be wiped off, white gills that turn black, slender white stem, and growth on cow patties and horse manure. Coprinopsis nivea was in Subsection Nivei of Section Veliformes of Coprinus sensu lato.

Cap:
up to 2.5cm high and 1.5cm wide when closed, ellipsoid, cylindrical-ellipsoid or subglobose, when expanded up to 4cm wide, conic or convex, finally applanate [flat] with slightly deflexed margin; completely covered at first with white, powdery veil, cap center often cream to pale ochraceous; veil at margin, particularly in early stages, somewhat more hairy-floccose, (Ulje), 1.5-4cm across, 2-3.5cm high, cylindric when young, soon conic - bell-shaped, "later expanded, often with an uplifted margin"; "white farinose-floccose when young, flocci can be wiped off", becoming bald "and somewhat translucent-grayish when old, especially toward the margin", margin +/- striate, "splitting and fimbriate-villose", (Breitenbach), 1-3cm high, bell-shaped; snow white, (Hansen, L.), cap "covered (as if with snow) by pure white, mealy-woolly veil"

Flesh:
thin and membranous; gray-black, (Breitenbach)

Gills:
free, L = 24-38, 1-3(5) subgills between neighboring gills; white at first, then gray to black, (Ulje), ascending and finely adnexed, 80-90 reaching stem, 1-3 between neighboring gills, gills broad; "white when young, soon gray, black when old"; edge white-flocculose, (Breitenbach)

Stem:
up to 10cm x 0.4cm, widening downwards, toward base up to 0.6cm wide; white, toward base often brownish with white veil flocks, (Ulje), 6.0-12.0 x 0.3-0.7cm, cylindric, widening downward somewhat, "base somewhat thickened", "hollow, fragile"; "entire surface snow-white-farinose-floccose on a whitish background", becoming bald when old, (Breitenbach), 5-7cm x 0.2-0.8cm, white; mealy, (Hansen, L.)

Veil:
cap completely covered at first with white, powdery veil, veil flocks toward stem base, (Ulje)

Odor:
none (Ulje, Breitenbach)

Taste:
indistinct (Buczacki)

Microscopic spores:
spores 12.2-19.0 x 10.8-15.6 x 7.5-9 microns, lentiform [lens-shaped], limoniform [lemon-shaped] in face view, elliptic in side view, "dark red-brown, with central to slightly eccentric germ pore"; basidia 4-spored, 25-40 x 12-16 microns, surrounded by 5-7(8) pseudoparaphyses; pleurocystidia 50-150 x 25-60 microns, "vesiculose, ellipsoid, or subcylindric", cheilocystidia 30-80 x 15-50 microns, similar to pleurocystidia; veil made up of up to 100 microns wide, (sub)globose elements; clamp connections sparse, probably just pseudoclamps, (Ulje), spores 15-19.3 x 8.5-11 x 11.2-13.9 microns, elliptic to almond-shaped, smooth, black-brown, with central germ pore; basidia 4-spored, 22-45 x 12-16 microns, clavate, some with basal clamp connection; pleurocystidia 60-145 x 35-65 microns, ovoid to ellipsoid, cheilocystidia 35-80 x 25-50 microns, subglobose to saccate; veil on cap of subglobose to ovoid cells 28-60 microns across, "encrusted in places, with occasional interspersed hyphoid elements" 3-10 microns wide, some septa with clamp connections, encrustation soluble in KOH, (Breitenbach), spores 12-18 x 10-11 x 7.5-9 microns, rounded hexagonal, flattened, (Hansen, L.), spores 12-18 x 10-13 x 8-10 microns; pleurocystidia abundant, (Moser)

Spore deposit:
"very dark chocolate brown, almost black", (Ulje), black (Breitenbach)

Notes:
Coprinopsis nivea has been found in WA (S. Trudell, pers. comm., Trudell(4)). There is a BC collection by O. Ceska at the University of British Columbia. It was examined from Netherlands and Switzerland (Ulje). Distribution includes North America, Europe, Asia, and Australia, (Breitenbach(4)).

EDIBILITY

Synonyms and Alternate Names:
Coprinus niveus (Pers.) Fr.
Coprinus niveus (Pers.) Fr.