[1] The species was originally found in 1948 in Cheboygan County, Michigan, USA, and described by mycologist Alexander H. Smith, who named it Coprinus subpurpureus.

[2] In 2001 a phylogenetic study resulted in a major reorganization and reshuffling of that genus and this species was transferred to Coprinellus.

The gills have an adnate attachment to the stem, and are narrow and placed closely together; they are buff in color before darkening to black in maturity prior to dissolving (deliquescing).

[2] The spores are smooth, elliptical or roughly oval depending on the direction in which they are viewed, and have dimensions of 12–14 by 5.5–6.8 by 7–8 μm.

[2] Coprinellus subpurpureus was found growing on wet leaves under hardwood trees in Michigan, USA.