Devil's Cigar Identification Guide

The setting, and why the setting is half the identification

There is no casual way to encounter this species. It is one of the most geographically restricted macrofungi known, recorded from a scatter of counties in central Texas and, remarkably, from a few forests in southern Japan, with essentially nothing in between. If you are standing anywhere else, the odds are overwhelming that you are looking at something else.

When you do find it, the setting is specific. In Texas, look on limestone-influenced slopes and dry creek terraces where cedar elm grows, particularly around old dead stumps and the buried root plates of trees that died some years ago. In Japan the associated wood is oak. Either way the fruitbody is not growing on soil in the ordinary sense: it is anchored to buried dead wood, and the visible base narrows into a dark cord that runs down to a root or a stump remnant.

Season matters just as much. Fruiting is a cool-weather event, broadly from mid autumn through early spring, with most records falling between December and February.

Step one: the unopened stage

Before it opens, the fruitbody genuinely looks like a discarded cigar butt pushed into the ground. It is an elongated, cylindrical to spindle-shaped club, typically 4 to 12 cm long and 1 to 3 cm thick, standing more or less upright or leaning.

The outer surface is dark brown to almost black, dry, and covered all over in a dense, coarse, shaggy or scurfy layer of matted hairs. Under a lens the hairs are stiff and dark. The texture in the hand is leathery and surprisingly tough — this is not a fleshy fungus that squashes; it flexes.

The apex is usually slightly pointed or blunt-rounded, and in a specimen approaching maturity you can often see the beginnings of the split as pale lines running down from the tip.

Step two: the opening, and what it reveals

The defining event is the split. At maturity the club tears open from the apex downward into four to seven — most often five or six — tapering rays, which peel back and curve outward until the whole thing sits like a dark leathery star on a short stalk. The opened body is commonly 5 to 12 cm across the spread rays.

When this happens in the field it is sometimes accompanied by an audible hiss and a visible cloud of spores, one of the few fungi in the world for which the moment of opening is a documented sound.

Now look at the inner faces of the rays. Where the outside is dark and hairy, the inside is pale — whitish, cream, pale tan, sometimes with a faint orange or salmon flush — and smooth to very finely roughened. That pale inner lining is the spore-bearing surface, the hymenium, and the contrast between the pale interior and the near-black hairy exterior is the single most useful photographic character.

Crucially, the interior is a simple open surface. There is no sac, no bladder, no membrane, no central pore, and no powdery mass of spores sitting in a chamber. Whatever the star shape suggests, this is an open cup that has been slit lengthways, not a puffball on a star-shaped base.

Step three: stalk, base and attachment

Follow the fruitbody down. The lower portion tapers into a distinct stalk, dark brown to black, tough, often partly buried, and usually 1 to 5 cm of it is visible above the leaf litter. Excavate carefully with fingers rather than a knife and you will normally find that the stalk continues as a dark, root-like extension into the soil until it meets dead wood. That anchor to buried elm or oak root wood is a habitat character you should record every time.

Step four: flesh and section

Cut a ray across. The wall is thin but tough — leathery to almost cartilaginous — and in section it shows a pale inner layer beneath the fertile surface with a dark, densely hairy outer skin. There is no jelly layer, no latex, and no colour change on cutting. Dried material becomes hard, dark and durable, and old opened stars can persist on the ground for weeks after they have finished releasing spores, gradually curling in on themselves.

Step five: spores, and why the usual print method fails

This is a cup fungus relative, not a gilled mushroom, so there is nothing to lay face down on paper. It discharges ascospores upward and outward from the pale inner faces of the rays.

To capture them, hold a glass slide or a card just above the open interior of a fresh specimen; specimens in active discharge will often puff spontaneously when jarred or warmed, and a fine pale dust settles on the slide. The deposit reads as whitish.

Under a microscope the spores are the confirming character and they are enormous by fungal standards: smooth, hyaline, spindle-shaped to narrowly elliptical, and roughly 50 to 70 micrometres long by 10 to 13 wide, borne eight to an ascus. Nothing else you would confuse it with in the field has spores anywhere near that size and shape.

Separating it from look-alikes on morphology alone

True earthstars. This is the confusion that trips up almost everyone, because both end up as stars on the ground. The difference is structural and absolute. An earthstar has two layers: an outer skin that splits into rays, and, sitting in the middle of those rays, a distinct round or flask-shaped spore sac with a defined opening — a pore, often with a raised or fringed mouth — through which puffs of powdery spores escape when a raindrop hits it. Our species has no sac at all. Cut it in half and you see one continuous leathery wall lining a hollow, with the fertile surface exposed directly to the air along the inner faces of the rays. Earthstars are also usually seated flat on soil or litter rather than raised on an obvious dark stalk, and they lack the shaggy dark pelt.

Devil's Urn. The other frequent mix-up, and a genuine relative. The urn is goblet or cup shaped, wider than tall relative to this species, and its opening is an irregular ragged tear at the top rather than a set of long, even, tapering rays running a third to half the length of the body. Its inner surface is dark brown to blackish, not pale. It is a spring fungus, most often on oak and hickory sticks in eastern North American woodlands, and its rim splits into short jagged teeth rather than peeling back into a symmetrical star.

Dark stalked cups generally. Several tough, dark, stalked cup fungi share the black exterior and rooting stalk, but they open as bowls, never as an elongated cigar that slits lengthwise, and their interiors are dark.

Stalked puffballs and dead plant material. Before opening, an unopened fruitbody can be mistaken for a stick, a piece of charred wood, a cigar butt or an old stalked puffball. Feel it: a stalked puffball has a papery head containing loose powder on a woody stalk, while this is a solid-walled leathery club with a hollow, not a powder-filled sac.

Recording a find

Given how genuinely rare this fungus is, treat any sighting as a record rather than a specimen. Photograph the unopened and opened stages, the pale interior, the hairy exterior, and the base with its attachment to buried wood; note the host tree species, the substrate depth, the aspect of the slope and the date; and leave the fruitbody in place to finish discharging. Repeat visits to the same stump in the same weeks of following winters are often productive, since the underlying mycelium persists in the dead root system for years.