Until an in-depth, species-level DNA study of coprinoid mushrooms is done, most of the species are still defined as they have always been defined--which means using a microscope if you want to identify them successfully. While naked-eye features can narrow down possibilities, especially with some of the larger species, microscopic differences have been used to define most of the coprinoid species. Spore morphology is often important, as is the anatomy of the pileipellis, the hymenium, and the veil elements. I recommend using a KOH mount, stained with something like phloxine, in order to see the features that define coprinoid mushrooms. A Roman aqueduct section provides a good start for microscopic analysis, but you may find you need to "scalp-section" the center portion of young caps in order to find veil elements; slice a very thin strip from the cap surface.
The authoritative online treatment of Coprinus is Kees Uljé's All about Inky Caps. Before his death in 2003, Uljé published extensively on Coprinus, and his Web site includes keys and descriptions for about 150 species. Kees was a wonderful, kind man, and he will be sorely missed. Unfortunately, the homepage for Kees's Web site was on a different server than the keys and species descriptions, and as of February 2008 his homepage has disappeared. The link above will lead you to his keys and mushrooms, however, and this link still works for Kees's type studies of several dozen coprinoid taxa.
Key to 81 North American Coprinoid Taxa
Note: With a few exceptions, I have included only taxa that have been reported from North America in one of the sources listed below the key.
|1.||Mushroom fairly large (mature cap usually over 5 cm); whitish with brownish scales, at least over the center; oval when young; gills whitish to pinkish when young, turning to black goo with maturity; stem with a ring, hollow when sliced, with a strand of fibers running through the hollow cavity; often growing in grassy urban areas, or in disturbed ground (ditches, roadsides, etc.) but not on dung; hymenial cystidia absent.|
|1.||Not completely as above.|
|2.||Known from the Pacific Northwest; stem 35-50 cm long; spores 17-20 µ long.|
|2.||Distribution various; stem much shorter than above; spores 8-18 µ long (Coprinus comatus in the wide sense).|
|3.||Spores with a central apical pore; widely distributed in North America.|
|3.||Spores with an eccentric pore; distribution uncertain (varieties originally recorded from western North America).|
|4.||Spores 8-15 µ long; pore slightly eccentric.|
|5.||Growing on dung or manured soil--sometimes on compost or decaying straw.|
|6.||Ring usually present on stem.|
|7.||Mature cap tiny (usually under 1 cm across); spores shaped like fat lemons.|
|7.||Mature cap larger than above; spores variously shaped. The subsequent species are reminiscent of miniature, dung-loving shaggy manes.|
|8.||Growing on the dung of horses or cows.|
|8.||Growing on the dung of wild animals (deer, rabbits, etc.).|
|9.||Stem to 8 cm high and 4 mm thick; spores 14-18 µ long.|
|10.||Mature cap 5-6 cm across; stem white, becoming brownish to black; spores "clear translucent chestnut brown" in KOH; clamp connections present.|
|10.||Mature cap under 4 cm across; stem white becoming pinkish at the apex; spores nearly black in KOH; clamp connections absent.|
|11.||Mushroom arising from sclerotia (black knots of tissue up to 1 cm across) that are buried in the, um, substrate; mushroom identifier, having determined this, quite possibly in need of a new hobby.|
|11.||Mushroom not arising from sclerotia.|
|12.||On the dung of cows; recorded from one location in the Netherlands, and from Hawaii; perhaps to be expected in North America.|
|13.||Cap up to 4 cm across, snow white when young, covered with soft mealy granules that are easily wiped off; found primarily on the dung of cows; spores 15-19 µ long.|
|13.||Not completely as above.|
|15.||Velar sphaerocysts also present on cap surface.|
|15.||Velar sphaerocysts absent.|
|18.||On dung, compost, or straw; pileocystidia thin-walled; pleurocystidia absent; clamp connections absent.|
|18.||Usually on dung; some pileocystidia thick-walled; pleurocystidia present; clamp connections present.|
|20.||Spores 9.5-13 µ long, with an eccentric pore; some pileocystidia with thick walls.|
|20.||Spores 6-9.5 µ long, with a central pore; all pileocystidia with thin walls.|
|21.||Clamp connections absent.|
|22.||Spores with a central pore.|
|23.||Spores lacking a sheath.|
|24.||Spores rounded-triangular to heart-shaped; cap under 1 cm across.|
|24.||Spores not as above; cap variously sized.|
|25.||Velar elements on cap round or nearly so (scalp-section the disc of young specimens).|
|25.||Velar elements on cap sausage-shaped to tubular or slightly inflated, in chains--but not round.|
|26.||Mature cap 10-25 mm across; veil elements smooth or slightly granular but not warty.|
|27.||Mature cap generally more than 15 mm across.|
|27.||Mature cap generally less than 15 mm across.|
|28.||Spores 9.5-11 x 6.5-7.5 µ; stem often rooting; pleurocystidia usually numerous.|
|28.||Spores 11-17 x 7-10 µ; stem not rooting; pleurocystidia sometimes absent or rare.|
|30.||Growing from logs, fallen trees, or large branches--or at the bases of stumps, or from the (usually dead) roots of trees, appearing terrestrial.|
|30.||Growing elsewhere . . . on wood chips; on straw, plant material or sticks; on organic compost; in grass; in disturbed ground; from carpet.|
|31.||Stem with a ring; growing on the wood of alders in western North America; cap to about 2 cm across.|
|31.||Stem without a ring; wood preference, range, and other features variable.|
|32.||Mature cap about 1 cm across, or smaller.|
|32.||Mature cap generally larger than 1 cm across.|
|33.||Known from the Pacific Northwest; growing alone on conifer sticks; young cap whitish to grayish under dark gray to black veil; deliquescence only occurring on the edges of gills; pileipellis a cutis; pileocystidia and velar sphaerocysts absent.|
|33.||Widely distributed in North America; growing densely gregariously on wood, especially at the bases of stumps or from decaying roots; cap whitish to grayish, without veil; gills not deliquescing; pileipellis an epithelium; pileocystidia and velar sphaerocysts present.|
|34.||Mushrooms arising from a rust colored to orange carpet of fuzz (an ozonium); pileipellis an epithelium.|
|34.||Mushrooms not arising from an ozonium; pileipellis variable.|
|36.||Cap prominently scaly.|
|36.||Cap with granules, hairs, tiny scales over the center only, scattered tiny scales--or relatively naked.|
|38.||Cap rusty brown, without veil; stem under 5 mm thick; pileipellis an epithelium with brownish setae; spores 13-16.5 µ long, smooth.|
|38.||Not completely as above.|
|39.||Young cap not whitish; spores smooth or warty.|
|40.||Young cap yellow, brownish yellow, honey colored, yellowish, brownish orange, or orangish.|
|40.||Young cap gray to brown or brownish.|
|41.||Veil disposed as mica-like granules on cap surface; velar sphaerocysts present.|
|41.||Veil absent, or tissue-like; velar sphaerocysts absent.|
|42.||Caulocystidia present. (Note: preliminary DNA evidence suggests that Coprinellus micaceus and Coprinellus truncorum may be genetically identical.)|
|43.||Cap surface smooth or, with a hand lens, very finely hairy; spores warty; pileocystidia present.|
|43.||Cap surface with tissuelike veil that breaks up into soft scales; spores smooth; pileocystidia absent.|
|44.||Spores broadly elliptical or nearly round (5.6-8.4 x 4.2-5 µ); apparently known from a single 1965 collection under alder in a Washington (state) campground.|
|44.||Spores more narrowly elliptical than above.|
|45.||Center of cap depressed; apparently known from a single 1972 collection "around a willow tree in a mixed forest" in Washington.|
|45.||Center of cap not depressed; widely distributed, common, and well documented in North America.|
|46.||Found in arid, desert or semi-desert ecosystems in western North America.|
|46.||Found in other ecosystems.|
|47.||Gills absent or poorly formed.|
|47.||Gills present and "normal."|
|48.||Mature cap disclike, with gill-like plates on its underside; volva present at stem base (often underground).|
|48.||Mature cap rounded-cylindrical, more or less like a shaggy mane cap; volva absent.|
|49.||Mushroom 15-45 cm high at maturity; stem 1.5-3 cm thick at apex; in North America known from southern California, southern Arizona, and southern Texas (and probably to be expected in Mexico); spores mostly under 10 µ long, with a distinct pore.|
|49.||Mushroom smaller than above (under 20 cm high, with stem up to 1.5 cm thick at apex); distributed throughout western and southwestern North America; spores variously sized, with or without a distinct pore.|
|50.||Most spores under 7.5 µ long, with an inconspicuous pore or without an apparent pore.|
|51.||Spores ellipsoid, generally under 7 µ long; gleba olive brown to yellowish brown.|
|51.||Spores subglobose, generally longer than 7 µ long; gleba reddish brown.|
|52.||Cap adorned with one or more large patches of veil.|
|52.||Cap without large patches of veil.|
|53.||Cap with a single, star-shaped, central patch.|
|53.||Cap with one or several patches, but not as above.|
|54.||Cap 1-6 cm wide, rusty brown, without veil, at maturity lined from the margin to the rusty brown center; stem under 5 mm thick; pileipellis an epithelium with brownish setae; spores 13-16.5 µ long, smooth.|
|55.||Cap up to 7 cm high, dark brown and then black, adorned with large, gorgeous, contrasting whitish scales; stem up to 30 cm long; spores 14-19 x 9.5-13 µ.|
|56.||Mature cap tiny (generally under 1 cm across); pileipellis a cutis.|
|56.||Mature cap larger than above--or if tiny, pileipellis not a cutis.|
|57.||Spores shaped like corn kernels, measuring 7-9 x 6-7.5 x 5-5.5 µ; known from Montana and Alberta.|
|57.||Spores otherwise shaped; distribution various.|
|58.||Veil hyphae with thick (over .5 µ) walls; spores 7.5-9 x 5.5-8 µ.|
|58.||Veil hyphae with thin walls; spore measurements various.|
|59.||Spores subglobose or elliptical, smaller than above.|
|60.||Veil hyphae hyaline; spores 5.5-8 x 4-5 µ; North American distribution uncertain, but possibly widely distributed; apparently harmlessly saprobic on rotting stems and leaves of various plants.|
|60.||Veil hyphae yellow-brown; spores 7-9 x 5-6 µ; known from Canada (British Columbia to Ontario); mycelium parasitic as a winter "snow mold" on various plants (follow the link to the right and scroll to the "Coprinus Snow Mold" section for photographs).|
|61.||Mature cap medium sized (at least 3 cm across), honey yellow to yellowish, adorned with mica-like granules.|
|61.||Mature cap variously sized, variously colored, lacking mica-like granules.|
|62.||Caulocystidia present. (Note: preliminary DNA evidence suggests that Coprinellus micaceus and Coprinellus truncorum may be genetically identical.)|
|63.||Mushroom appearing like a miniature shaggy mane, with a cap up to 3 cm across and a stem up to 7 mm thick; spores about 9-10 µ long; known from the Pacific Northwest and from Germany.|
|64.||Cap fairly large (3-10 cm when mature), appearing naked or with small, inconspicuous scales over the center, gray to grayish brown or brown; pileipellis a cutis; hymenial cystidia conspicuous.|
|64.||Not completely as above.|
|65.||Spores broadly elliptical or nearly round (5.6-8.4 x 4.2-5 µ); apparently known from a single 1965 collection under alder in a Washington (state) campground.|
|65.||Spores more narrowly elliptical than above.|
|66.||Center of cap depressed; apparently known from a single 1972 collection "around a willow tree in a mixed forest" in Washington.|
|66.||Center of cap not depressed; widely distributed, common, and well documented in North America.|
|67.||Cap surface smooth or grooved, but naked--without (macroscopic) evidence of a veil, even in button stages (though surface may appear very finely hairy or pubescent with a hand lens, before the pileocystidia collapse); pileocystidia present or absent.|
|67.||Cap surface with evidence of a veil, at least when young; pileocystidia always absent.|
|68.||Fresh cap with purplish hues.|
|68.||Purplish hues absent.|
|69.||Spore print with reddish hues; possibly not collected since the 1949 type collection (from a lumber yard in Dexter, Michigan).|
|72.||Spores mitre-shaped (like a bishop's hat); growing from charcoal in old burn sites.|
|72.||Spores more or less elliptical, ovoid, oval, or subglobose; habitat variable.|
|73.||Cheilocystidia mostly subglobose.|
|73.||Cheilocystidia mostly bottle-shaped, fusoid-ventricose, lageniform, etc. (Coprinus expert Kees Uljé writes: "In species with predominantly globose cheilocystidia . . . a few lageniform ones are sometimes present. In some species with mixed globose and lageniform cheilocystidia, the latter are not always abundant. Therefore identification is not easy. Fortunately there are other characters that may help.")|
|74.||Pileocystidia subcapitate; spores 9-14 x 5.5-7 µ, with a slightly eccentric pore; growing alone, widely scattered, or in loose groups on sticks, litter, grass, wood chips, and muck.|
|74.||Not completely as above.|
|75.||Pileocystidia variable in shape, frequently with thick, yellowish to brownish walls; spores 10.5-15 x 5-7.5 µ, with an eccentric pore; growing scattered to gregariously or in clusters on soil rich with litter or woody debris, especially in disturbed-ground locations, or on lawns; in North America suspected from Idaho.|
|75.||Not completely as above.|
|76.||Usually found near woody debris (including wood chips) in disturbed-ground areas like paths and ditches; cheilocystidia exclusively subglobose; spores 6-7.5 µ wide; some or many pileocystidia with thick walls present.|
|76.||Usually found in naked soil, muck, or mull; cheilocystidia often polymorphic, ranging from subglobose to lageniform; spores 6-8 µ wide; thick-walled pileocystidia rare or absent.|
|78.||Growing gregariously on fallen sticks near Mt. Hood and possibly not collected since the 1947 type collection; pileocystidia short (40-70 µ long), with tapering necks; spores very broadly elliptical, measuring 8.5-10.5 x 7-8.5 µ.|
|78.||Habitat various; pileocystidia longer and spores less broadly elliptical than above.|
|79.||Growing in dense clusters in grass; veil present as chained, subcylindric to subfunky elements (scalp-section the disc); pileocystidia lageniform, tapering, always with thin walls; spores 7.5-11.5 x 4.5-6 µ.|
|79.||Growing alone, scattered, or in loose clusters in bare soil or grass; veil elements absent; pileocystidia tapering or not, sometimes with thick walls; spore measurements various.|
|80.||Pileocystidia cylindric or tapering only slightly, with thick-walled pileocystidia usually present; spores 9-14 x 6-8 µ, with an eccentric pore.|
|80.||Pileocystidia tapering substantially, always with thin walls; spores 10.5-11.5 x 6-7.5 µ, with a central or slightly eccentric pore.|
|81.||Spores 13-19 x 7-9.5 µ, with an eccentric pore; cap yellowish when young; veil with subglobose elements mixed in with tubular and sausage-shaped elements.|
|81.||Spores shorter than above, with or without an eccentric pore; young cap variously colored; veil elements mostly tubular to sausage-shaped, rarely subglobose.|
|82.||Spores with a sheathlike outer covering.|
|82.||Spores without a sheathlike outer covering.|
|83.||Spores subglobose to broadly lemon-shaped, 7-9 x 6-7.5 µ; growing alone in a Washington lawn in 1968 and now preserved as "[o]nly a stipe, a part of stipe with collapsed pileus as a black mass at apex and a small part of a pileus" (Uljé), and possibly otherwise undocumented.|
|83.||Spores elliptical, 11-15 x 7.5-9 µ; growing in a Washington greenhouse in 1950 and possibly otherwise undocumented.|
|84.||Spores subglobose to very broadly elliptical or broadly lemon-shaped.|
|84.||Spores more narrowly elliptical.|
|85.||Growing as a pest in commercial mushroom farm compost; spores globose to subglobose.|
|85.||Growing elsewhere (often near woody debris in woods, or in burned areas); spores subglobose to broadly lemon-shaped.|
|86.||Veil present as a dense covering of white hairs over a mouse gray cap surface; spores 10.5-13.5 x 7-8.5 µ, with a central pore; common and widely distributed in North America.|
|86.||Veil and cap not colored as above (gray-on-gray, tan-on-brown, or colorless-on-brown instead); rare species apparently known only from type collections in the Pacific Northwest (though one species has since been found in England).|
|87.||Veil scant, even in buttons, visible as "minute reddish brown scales or filaments"; spores 14-15 x 7-8 µ, with an apical pore; growing near woody debris of conifers.|
|87.||Veil more prominent than above, either colorless or tan; spores 9-11.5 µ long, with an apical or eccentric pore; habitats various.|
|88.||Cap with tan veil on a brown surface; spores with an eccentric pore.|
|88.||Cap with colorless to brownish veil on a whitish surface that becomes brownish; spores with an apical pore.|
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Cite this page as:
Kuo, M. (2008, February). Coprinoid mushrooms: The inky caps. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/coprinoid.html