Scaly Inkcap Identification Guide

The first impression

The usual encounter is a dense, crowded cluster of medium-sized caps erupting from a rotting hardwood log, a buried stump, a heap of chipped wood or the sawdust-rich soil beside a felled tree, in summer or early autumn after warm rain. The caps are egg-shaped to bell-shaped, tan to ochre-brown, and they look as though someone has pressed torn scraps of buff-coloured felt all over them. The clustering is important: this species characteristically comes up many together with the stipe bases converging, not as scattered singletons.

The second impression, if you come back a day later, is a puddle of black liquid where the group was. That self-digesting habit tells you immediately which family you are in, and it also means the identification has to be done on fresh or freshly opened material.

Reading the cap

Start with shape. Young caps are ovoid to cylindric-ovoid, 3 to 8 cm tall, then expand to broadly bell-shaped and finally flatten and split radially at the margin as the whole thing starts to liquefy. The underlying skin is tan, ochre-brown or warm greyish-brown, paler toward the margin, and it is finely radially lined, with the lines becoming grooves as the cap opens.

Over that skin lies the universal veil, and it is the veil that supplies the scaliness. It starts as a continuous woolly-felty coat and breaks up into irregular buff, cream or pale ochre patches and flakes, largest and most persistent at the centre of the cap and progressively smaller and more scattered toward the edge. These patches sit loosely: rain, handling or a strong wind removes them, and a weathered cap can look almost bare. Always look at the youngest cap in the cluster to judge the veil.

The gills

Gills are crowded, narrow and free or only just reaching the stipe. Their colour sequence is the standard inkcap progression and should be checked deliberately: white and clean in a closed button, then greyish, then a smoky pinkish-grey, then black from the margin inwards as they autodigest. In a mature specimen the lower edge of the cap is already dissolving into an inky drip.

That sequence is diagnostic at family level. If the gills are dark but firm, dry and not dissolving after several hours in a box, you are not looking at an inkcap.

The stipe, ring and base

The stipe is white to dirty cream, 5 to 12 cm long, hollow, slightly fibrillose and often minutely scaly-hairy toward the base, tapering upward. Because the fruitbodies grow tightly packed, stipes are frequently curved or flattened where they press together.

Two base characters deserve attention. First, the very bottom often narrows into a rooting extension that runs down into the rotten wood or the wood-chip layer, so pulling a specimen out will usually snap it; dig instead. Second, some collections show a faint, low, collar-like rim or an ill-defined ring zone low on the stipe, a remnant of the veil, rather than a well-formed pendant ring. Record it if present, but do not expect it every time.

Flesh and colour change

The flesh is thin, whitish and fragile, and there is no dramatic bruising reaction. What you will see instead is progressive blackening as autodigestion sets in from the cap margin. Cutting a young button lengthways is worth doing anyway, because a clean section shows the veil layer as a distinct outer coat and confirms how the gills attach.

Taking and reading a spore print

A spore print is easy and unusually satisfying with an inkcap, provided you catch the timing. Take a cap just as the margin begins to darken, cut the stipe off flush, and set the cap gills-down on white paper under a cup for two to four hours. Because the gills are dissolving, the print comes fast and can be genuinely black and slightly liquid rather than a dry dust. Leave it too long and you get an ink blot rather than a print.

The deposit reads deep black. Under a microscope the spores are smooth, dark, more or less ellipsoid, and carry a distinct central germ pore at the apex, which is a family character worth learning to see.

Substrate and season

This is a decomposer of dead deciduous wood. Look on rotting logs and stumps of broadleaf trees, on buried wood, in wood-chip mulch on park and garden beds, on sawdust piles and along the line of an old removed hedge where roots are decaying underground. Fruiting is mostly summer to early autumn, sometimes earlier than the main mushroom season, and it responds quickly to warm wet spells. A single site can produce successive flushes over several weeks.

Always confirm the wood connection. If the cluster is genuinely growing in grassland turf with no wood beneath, look elsewhere in the genus.

Separating it from the look-alikes

Magpie Inkcap, Coprinopsis picacea. The closest visual match and the one to check first. It is taller and usually solitary or in twos, its cap ground colour is a very dark blackish-brown, and the veil remnants are large, sharply contrasting pure white patches, giving a genuinely piebald look. It also favours leaf litter on calcareous soil under beech rather than clustering on rotten wood.

Common Inkcap, Coprinopsis atramentaria. Similar size and clustering habit, but the cap is smooth, greyish to greyish-brown, often dented or bruised-looking, and lacks the felty buff patches entirely apart from a few scurfy scales right at the apex.

Glistening Inkcap, Coprinellus micaceus. Smaller and tawny to date-brown, and its veil is not felty patches but a scatter of tiny glistening granules that look like sugar and vanish quickly. Its caps are strongly grooved and it clusters on stumps in similar places.

Firerug Inkcap, Coprinellus domesticus. Look at the substrate surface: this species sits on a conspicuous orange-brown felty mat of mycelium spread across the wood, which is unmistakable when present.

Hare's Foot Inkcap, Coprinopsis lagopus. Much more fragile and short-lived, greyish, clothed when young in soft whitish hairs rather than discrete felty plates, with a very thin stipe, typically on litter and chips.

Shaggy Inkcap, Coprinus comatus. No real confusion once seen: tall and cylindrical, white with large shaggy upturned scales in the outer layer of the cap itself, a movable ring, and a habit of appearing in grass and on verges.

A quick field checklist

Crowded cluster on rotting hardwood or wood chips, tan cap with loose buff felty patches, radially lined margin, gills running white to grey to black and liquefying, hollow whitish stipe with a rooting base and at most a faint low ring zone, and a jet-black print.