Coprinus Genus

Key to Gilled Mushrooms Key

This is a key to gilled mushrooms, that is, mushrooms having a definite cap with a fertile surface consisting of gills. The fruiting body usually also has a stem, although that may be lateral or absent (usually, then, the mushroom is growing from wood). You can use this key to identify mushrooms that you find.

Agaricales Order

Fruiting body containing fibers (usually in the stalk)

Black Spored Suborder

Spore print black, very dark brown, purplish black, or dark purplish brown, but not fitting the Gomphidiaceae
Gills usually light grey, becoming black from spores only when very mature

Coprinus Genus (Persoon: Fries) S. F. Gray

Diagnosis

All deliquescing fungi go here
All striate or pleated-capped non-Gomphidius black-spored mushrooms go here (but not randomly wrinkled ones: they go in Psathyrella)
When young, the cap usually cylindrical, and in any case much taller than it is wide and hugging the stem tightly; the gills at this stage are white, and packed very close together
Cap usually deliquescing and surviving in age as uplifted tatters or split fragments
Cap often covered with powder or tiny hairs, especially when young

Comments

I had never heard that the Coprinus species were confused (recently DNA implications for nomenclature aside), so I was surprised when I had to synonymize several species. There are several cases where the descriptions two species (sometimes even in the same book!) were indistinguishable from one another

Narrow down your identification:

Large Shaggy Scaly Inky Section

Cap up to 6" high; white, silvery, or some light greyish brown color; covered with fibrillose shags or scabby-looking white to brownish patches of universal veil material

Small Pleated NonInky Section

Cap up to 3/4" across; pleated; not deliquescing in age, just becoming darker

Small Powdery Inky Section

Cap up to 1" high, opening to about the same width; covered with tiny, fragile fragments of universal veil material, which may take the form of either flakes or hairs; greyish brown, with a warmer brown disk
Stalk hollow, also covered with the same sort of universal veil material

Coprinus atramentarius

Cap a uniform light grey (sometimes a bit silvery) or greyish brown, except where the color of the gills is showing through; up to 4" high; striate all the way to the disk
Stalk hollow

Lookalikes:

Bolbitius Genus

Cap slimy, deliquescing in maturity; striate, at least in maturity
Cap fragile, hollow

Pluteus Genus

Spores pink.
This will give the gills a pinkish tinge after a few hours in the collecting basket.

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Coprinus Genus

Coprinus Genus

Fruiting body containing fibers (usually in the stalk)

Spore print black, very dark brown, purplish black, or dark purplish brown, but not fitting the Gomphidiaceae Gills usually light grey, becoming black from spores only when very mature

Coprinus Genus (Persoon: Fries) S. F. Gray

Diagnosis

Comments

Narrow down your identification:

Cap up to 6" high; white, silvery, or some light greyish brown color; covered with fibrillose shags or scabby-looking white to brownish patches of universal veil material

Cap up to 3/4" across; pleated; not deliquescing in age, just becoming darker

Cap up to 1" high, opening to about the same width; covered with tiny, fragile fragments of universal veil material, which may take the form of either flakes or hairs; greyish brown, with a warmer brown disk Stalk hollow, also covered with the same sort of universal veil material

Cap a uniform light grey (sometimes a bit silvery) or greyish brown, except where the color of the gills is showing through; up to 4" high; striate all the way to the disk Stalk hollow

Lookalikes:

Cap slimy, deliquescing in maturity; striate, at least in maturity Cap fragile, hollow

Spores pink. This will give the gills a pinkish tinge after a few hours in the collecting basket.

Spore print black, very dark brown, purplish black, or dark purplish brown, but not fitting the Gomphidiaceae
Gills usually light grey, becoming black from spores only when very mature

Cap up to 1" high, opening to about the same width; covered with tiny, fragile fragments of universal veil material, which may take the form of either flakes or hairs; greyish brown, with a warmer brown disk
Stalk hollow, also covered with the same sort of universal veil material

Cap a uniform light grey (sometimes a bit silvery) or greyish brown, except where the color of the gills is showing through; up to 4" high; striate all the way to the disk
Stalk hollow

Cap slimy, deliquescing in maturity; striate, at least in maturity
Cap fragile, hollow

Spores pink.
This will give the gills a pinkish tinge after a few hours in the collecting basket.