Black Tooth Identification Guide

The Moment You Spot It

Black Tooth rarely announces itself. Nine times out of ten you are walking an old, undisturbed pine wood on sandy, nutrient-poor ground, eyes down on a mossy bank or the edge of a sunken track, and something reads as a scrap of charred wood or a piece of dark felt pressed flat into the moss. It sits low, matt and light-absorbing, often in a group of several caps that have grown into one another to form a lumpy compound plate. The first useful action is simply to touch it. Charcoal is brittle and smears; this is firm, springy-tough and rooted in the ground. The second action is to lever one specimen up and turn it over, because everything that matters is on the underside.

Reading the Cap

Individual caps run roughly 3-7 cm across but are seldom neat circles. They are irregular, kidney-shaped or fan-shaped, and repeatedly fuse sideways with neighbours until a colony can cover 20 cm or more of ground. Young caps are finely velvety and matt, slate-grey to blue-black, frequently with a paler grey or almost whitish growing rim. As they age the centre becomes blackish, roughened, radially fibrous and marked with faint concentric zones, and the surface may become pitted or lumpy.

One habit worth knowing: fungi in this family grow around whatever is in their way. Pine needles, grass blades and moss stems are routinely engulfed and end up standing through the cap flesh. A cap with vegetation growing straight out of it is a good sign you are in the right group.

The Toothed Underside

Turn it over and you find neither gills nor pores but a dense pile of short spines, generally 1-3 mm long, crowded together and running down onto the stem so that the join between cap and stipe is blurred rather than abrupt. Fresh spines are pale: whitish, ash-grey, sometimes with a faint lilac or violaceous cast in very fresh material, drying to grey-brown. They are firm rather than fragile and do not shed easily when rubbed. That combination of pale, short, decurrent teeth under a near-black cap is the single most memorable feature of the species.

Stipe and Base

The stipe is short and stout, often only 1-4 cm tall and sometimes shorter than the cap is wide, so the whole fruit body squats. It is blackish, felted or velvety like the cap, and tapers downward into a tomentose base that binds sand, needles, moss and soil into a matted plug. Lift carefully with a knife so this base comes up intact; a clean-cut stipe loses useful information.

Flesh and the Duplex Test

Slice the fruit body vertically from cap edge through the stipe. The flesh is tough and corky rather than soft or watery, and it is built in two layers: a softer, more fibrous zone immediately beneath the cap surface, and a harder, darker, almost woody layer below it. Look also at the stipe flesh, which is typically blackish with concentric banding. This two-layered, or duplex, construction is the genus character that carries you through most identifications. There is no milk or latex, and no dramatic bruising reaction, though a cut face may darken slightly as it dries.

Smell is a genuinely diagnostic character here, and it is best read on dried material. Put a fragment in a paper envelope, leave it a day or two indoors, then open it: the strong sweet-aromatic fenugreek or curry scent is unmistakable and confirms the group.

Taking a Spore Print

A toothed fungus is more awkward to print than a gilled one, but it is worth the effort because the print colour draws a hard line through the whole tooth-fungus group. Cut a thin slice of cap carrying a patch of spines, lay it spine-side down on dark glass or black card, cover it with a tumbler to hold humidity, and leave it somewhere cool overnight. A mature specimen gives a white deposit, which shows far better against a dark background. Under the microscope the spores are near-spherical, colourless and covered in short blunt spines.

Substrate, Season and Setting

Black Tooth is ectomycorrhizal, so it always comes out of soil or moss, never out of wood. The classic setting is old Scots pine or spruce woodland on thin, sandy, acid soil, plus mossy tracksides, heathy woodland edges and sometimes oak or beech on similarly poor ground. Fruiting runs from late summer through autumn, and a productive patch tends to come back to exactly the same square metre year after year, so it is worth marking the spot. Old fruit bodies blacken and persist for weeks, which means you can find identifiable remains long after the flush.

Separating the Look-Alikes

Work outward from spore colour and flesh texture.

Other Phellodon species share the white print and duplex flesh. Phellodon melaleucus and P. connatus have thin, almost membranous caps, paler grey-brown with a distinct white margin, and slender wiry black stipes. P. confluens is paler buff-brown, thicker and more heavily felted, forming broadly fused plates but never that blue-black tone. P. tomentosus is small, thin, concentrically zoned orange-brown and usually funnel-shaped.

Hydnellum species are the commonest confusion. They have brown spore prints, and their flesh, while tough, is more strongly zoned and often pinkish-, orange- or rust-tinged rather than divided into two clean layers. Their teeth usually darken to brown. If your print is brown, you are not in Phellodon.

Sarcodon species are altogether larger and fleshier, with coarse teeth several millimetres long, a scaly or cracked brown cap and a brown spore print.

Bankera fuligineoalba also gives a white print and also smells of fenugreek when dried, but the cap is pale buff to dirty whitish-brown rather than black, and the flesh is not duplex.

Boletopsis looks superficially similar and grows in the same pine woods, but its underside carries pores, not spines.

A Working Field Sequence

Confirm teeth rather than gills or pores; confirm the fungus emerges from soil; check for pale, short, decurrent spines beneath a black velvety cap; cut vertically and look for corky, two-layered flesh; bag a piece to dry for the fenugreek check; print it for white spores. If all six line up in acid conifer woodland in autumn, Black Tooth is a solid call.