Coprinellus disseminatus

Scientific name: Coprinellus disseminatus (Pers.) J.E.
Lange
Derivation of name:  Copr- means "dung" and ellus is
diminutive. Disseminatus means "dispersed."
Synonyms: Coprinus disseminatus (Pers.) Gray  
Common name(s): Non-inky Coprinus, little helmuts.  
Phylum:   Basidiomycota
Order:   Agaricales
Family:   Psathyrellaceae
Occurrence on wood substrate: Saprobic; on
deciduous wood debris, at the bases of stumps, in grassy
areas growing from the decaying roots and buried
remains of stumps; spring through fall.
Dimensions:  Caps 0.5-2.0 cm wide; stipes up to 4 cm
tall and 0.5-2 mm thick.  
Cap: Bell-shaped or convex; white to cream at first,
becoming brownish-gray with a yellow-brown disc;
deeply pleated (furrowed) from the margin almost to the
disc.        
Gills: Attached to stipe or free from it; white, becoming
blackish in age but not liquefying (inky), or perhaps only
slightly.
Spore print: Blackish.
Stipe: Slender, fragile, whitish, hollow.
Veil: Absent.
Comments: This species used to be in the genus Coprinus
but DNA studies radically revised the taxonomy of that
genus: Coprinus was retained for a small number of
species, several new genera were created, and the
members of the family Coprinaceae were split between
two families - Psathyrellaceae and Agaricaceae.

More information at MushroomExpert.com
  

Figure 1. This strip of grass between the street and the
sidewalk is supporting the growth of thousands of tiny
Coprinus disseminatus fruitbodies. Photo © Gary
Emberger.


Figure 2. Same fruiting as Figure 1. A large pin oak
(Quercus palustris) tree once grew on this site. Although
most of the stump was ground out, many dead roots and
decaying wood chips remained to support the growth of
this fungus. Photo © Gary Emberger.


Figure 3. The Basidiomycota Checklist-online describes
this species as fruiting in "vast, densely gregarious swarms."
Photo © Gary Emberger.

Figure 4. The caps are deeply pleated from the margin
almost to the center. Photo © Gary Emberger.

Figure 5. Caps are typically grayish toward the margin and
have a yellow-brown disc. Photo © Gary Emberger

Figure 6. Widely-spaced gills are white at first and become
darker as the black spores mature. Photo © Gary Emberger.

Figure 7. The caps and gills do not liquify into a black ink.
However, touching the moist caps will turn your fingers black.
Eventually, they dry and shrivel up. Photo © Gary Emberger.


Figure 8. Spore prints and shriveled caps of several
specimens on a glass slide. Photo © Gary Emberger.