Devil's Urn Identification Guide

The first impression

Early spring, an eastern hardwood woodland, the ground still mostly brown and bare. You are walking a slope of oak and hickory and you notice what looks like a handful of small burnt paper cups scattered across the leaf litter. They are dark — brown-black to charcoal — leathery rather than fleshy, and they stand upright on short dark stalks. Some are still closed, looking like blackened clubs or shoe buttons pushed out of the ground; others have torn open into ragged goblets.

The usual mistake at this point is to assume they are growing from soil. They are not. Sweep the litter away and follow the base of each fruitbody down: there will be a buried stick, branch or root, usually oak or hickory, generally well rotted and often surrounded by a mat of black mycelium that binds leaf fragments and soil into a dark crust. Establishing that attachment is the single most valuable minute you can spend on this identification.

Step one: shape and stage

This species passes through two visually distinct stages and you should learn both.

The closed stage is a dark, hard, more or less club-shaped or barrel-shaped body, 2 to 5 cm tall, with a rounded or slightly pointed top and no opening. It feels tough and dry.

The open stage is the classic urn: a deep goblet or vase 3 to 7 cm across the mouth and 4 to 10 cm tall including the stalk. The cup is deeper than it is wide when young, gradually flaring with age. The opening is created by the top tearing apart, and the resulting margin is ragged, irregularly toothed and often incurved, sometimes with the torn flaps still hanging inward. It never opens as a clean circular rim, and it never splits into a neat symmetrical star.

Step two: the fertile surface

Look inside the cup. The inner surface is the hymenium and it is dark: deep brown to blackish-brown, sometimes with a greyish or slightly purplish cast when very fresh and wet. It is smooth to faintly wrinkled, matt rather than glossy, and it has no veins, ribs, folds, gills or pores. It usually pales a little as it dries.

That dark interior is a key character. Several genuinely similar spring cup fungi are equally dark outside but paler within, and any cup with a pale, cream, orange or reddish interior belongs elsewhere.

Step three: the outer surface

Run a fingertip up the outside. It is dark brown to black, dry, and distinctly roughened — scurfy, minutely scaly or velvety depending on age and moisture — never smooth and shining, never slimy, and never bearing the orange-red granules some black cups carry.

The roughening continues down onto the stalk and becomes coarser there. Under a lens the surface is made of short dark hairs and cell clusters, giving a fuzzy or granular look.

Step four: the stalk and base

The stalk is a genuine, well developed feature, not an afterthought: usually 1.5 to 4 cm long, blackish, tough, roughly cylindrical or slightly tapering downward, often curved to bring the cup upright from a horizontal stick. It is frequently partly buried, so measured length depends on how much litter you clear.

At the very bottom, look for black mycelium — a felty, sooty mat spreading over the wood and cementing debris. Its presence is characteristic and it is also useful for finding more fruitbodies, since a colonised branch usually produces several.

Step five: flesh and section

Cut a fruitbody vertically. The wall is thin — a couple of millimetres — and remarkably tough: leathery, rubbery, almost cartilaginous. It flexes rather than breaking, which is quite different from the brittle snap of a typical fleshy cup fungus.

In section you see a dark fertile layer lining the inside, a paler brownish layer through the middle of the wall, and a dark outer skin. There is no gelatinous zone, no thick jelly filling, no latex, and no colour change on cutting or on bruising. Old fruitbodies dry down to hard, blackened, persistent shells that can be found on the woodland floor long after the season, sometimes filled with rainwater.

Step six: getting a spore deposit

As an ascomycete, this fungus shoots its spores upward from the inner surface, so laying it on paper achieves nothing. Instead, prop a glass slide or a strip of dark card a couple of centimetres above the mouth of a fresh, wet cup inside a closed container and leave it for several hours.

An easier trick in the field: cup a fresh specimen in your hand and breathe warm moist air across the opening, or tap it sharply. A mature fruitbody in active discharge will release a visible pale puff, which is both satisfying and confirmatory.

The deposit reads whitish. Microscopically the spores are large, smooth, hyaline and elliptical — roughly 22 to 37 micrometres long by 9 to 15 wide — with eight per ascus, and the asci open by a lid. That size range comfortably separates it from the small-spored dark cups.

Step seven: substrate and season

The substrate is dead hardwood, most commonly oak, with hickory, beech and other broadleaf trees also recorded. Fruitbodies arise from fallen branches, buried sticks, root fragments and the litter directly over them, in mixed and deciduous woodland, often on slopes and along stream terraces.

Season is early spring and it is narrow: roughly March to May across most of its eastern North American range, beginning as soon as the ground thaws and finishing before the canopy closes. It is one of the first conspicuous fungi of the year, appearing at the same weeks as the other early spring ascomycetes, so a black leathery goblet found in September deserves a second look.

There is a second life stage worth knowing about. The same fungus produces a dark, crusty, asexual stage on standing oak wood, associated with a distinctive canker that develops on living trunks and branches — which is why colonies persist in a woodland for many years.

Separating it from its look-alikes on morphology alone

Black false plectania. Grows as a shallow to almost flat black disc, essentially without a stalk, seated on soil, moss or buried debris, often with conifers. Ours is a deep goblet on a clear stalk with a torn, toothed rim.

Black tulip cup. A montane and western spring species associated with conifers near melting snow, with a slender, comparatively long, often hairy black stalk and a smaller, neatly cup-shaped or tulip-shaped head with an even, unbroken margin.

Granular black cup. Similar dark colouring but generally smaller, shallower, and with conspicuous orange-red to rusty granules scattered over the outer surface, visible with a hand lens.

Gelatinous goblets. Some large dark spring cups have a thick, wobbly, jelly-filled interior; cut one across and it is obviously watery and gelatinous throughout, whereas our species is thin-walled, hollow and leathery.

Black bulgar. Rubbery black buttons or top-shaped bodies clustered directly on fallen oak bark, with a smooth, shining, disc-like upper surface, no stalk to speak of, and a dark spore deposit rather than a whitish one.

Devil's Cigar. A relative and the most interesting comparison. That species starts as an elongated hairy cigar and splits from the tip into four to seven long, even, tapering rays that recurve into a symmetrical star, exposing a pale cream to tan interior. Ours tears irregularly at the top into short ragged teeth and is dark brown to black inside. Their seasons and ranges also differ sharply.

Fleshy brown spring cups. Various large brown cup fungi of spring are thicker-fleshed, brittle, paler brown, often stalkless and sitting on soil or woodchips, and they lack the tough leathery wall.

Field summary

Deep dark goblet with a ragged toothed rim; blackish-brown interior; roughened black exterior; distinct blackish stalk; thin leathery unchanging wall; whitish spore deposit of large elliptical spores; attached to buried hardwood with black mycelium at the base; early spring in eastern deciduous woodland. Confirm the buried wood and the tough wall and you have it.