Black-footed Polypore Identification Guide

The first impression

A damp ravine, a streamside alder or willow, a fallen beech trunk half-buried in leaf litter. Standing out of the wood or the litter beside it is a thin, glossy, chestnut-brown disc, dished in the middle like a shallow funnel and carried on a slender dark stalk. In good light the cap looks varnished, and the darkest chestnut of the centre grades outward to a lighter tawny or almost yellow-brown rim.

Pick it and it is tough. The flesh is leathery rather than fleshy, the cap does not tear easily, and the stalk is hard. Turn it over and the underside is not gilled but poroid, and so finely so that at a glance it appears smooth and white.

Reading the cap

The cap runs 3 to 15 cm across and occasionally larger. Young caps are circular with a shallow central dimple; with expansion they become distinctly funnel- or vase-shaped when the stalk is central, or kidney-shaped and one-sided when the stalk is set off to the edge, which happens often on vertical faces of wood.

The surface is smooth, sometimes finely radially wrinkled towards the margin, and noticeably shiny or lacquered when moist. Colour is a deep chestnut to almost blackish red-brown at the disc, lightening to tawny, ochre or pale buff at the edge. The margin itself is thin and sharp, usually wavy or lobed, and it incurves and becomes brittle as the fruitbody dries.

Hold the cap up to a bright sky: because the flesh is so thin, the margin is often faintly translucent.

The pore surface

The spore-bearing layer is a tube layer, and it runs decurrent, extending down onto the top of the stalk before stopping abruptly. Colour is white to cream when fresh, ageing to straw or pale ochre and browning where damaged.

The pores themselves are the key. They are minute and round, roughly five to eight per millimetre, which means the naked eye reads the surface as smooth and it takes a hand lens to resolve individual openings. The tube layer is correspondingly shallow, only about half a millimetre to two millimetres deep. Any polypore whose pores are visible without magnification is a different species.

The stipe, and the character that names it

The stalk is 2 to 8 cm long and up to 1 cm thick, central on horizontal substrates and eccentric to almost lateral on vertical ones. It is solid, tough and slightly tapering.

Its colour is the identification. The lower half is black or blackish brown, and in well-developed material the black extends much further up, sometimes nearly to the junction with the pore layer, ending in a fairly sharp boundary against the white pores. The surface of the black portion is finely velvety or minutely tomentose when fresh, becoming smoother and shinier with age. Any pale zone is confined to the extreme apex.

Excavate the base if the fruitbody appears to be growing from soil. In most cases you will find it rooted into a buried branch, root or fragment of hardwood, which resolves the substrate question.

Flesh and cut surfaces

Cut a fruitbody vertically through cap and stalk. The flesh is thin, one to four millimetres in the cap, pure white to cream, and tough and pliant when fresh. On drying it becomes hard and horny, and dried specimens are almost impossible to cut with a thumbnail.

Nothing changes colour on cutting. There is no blueing, no reddening, no latex and no exudate, and the smell is faint and slightly fungal. The fruitbody is annual, so you will not find the stacked layers of tubes that mark a perennial bracket.

Taking a spore print

Because the fruitbody is tough and long-lived, an old one may have finished shedding altogether, so select a young, moist specimen with a clean white pore surface. Cut the cap free with a little of the stalk, lay it pore side down on dark card, cover it with a bowl and leave it overnight.

The print is white to very pale cream. Microscopically the spores are smooth, cylindrical to narrowly ellipsoid and inamyloid, and the flesh has a dimitic construction with skeletal hyphae, which is why the tissue is so tough. For field purposes the white print plus fine pores plus black stipe is sufficient.

Substrate, ecology and season

The Black-footed Polypore is a white-rot saprotroph of dead broadleaved wood, most often beech, willow, poplar, alder, oak, ash and lime, and only rarely on conifers. It fruits on fallen trunks, stumps, buried roots and large branches, especially where the wood lies in shaded, humid ground beside water.

The season is long, from late spring to late autumn, roughly May to November, with a broad peak in late summer and autumn. Fruitbodies come singly or in small groups of two or three from the same piece of wood, and because the dried remains are so hard they can be found long after the season, curled and blackened, still attached.

It is widely distributed across the north temperate zone and is a common component of the decay community on damp lowland hardwood.

Separating it from look-alikes

Picipes melanopus. The closest relative and the hardest call. It is smaller, its cap is a duller ochre-grey to pale greyish brown rather than a glossy chestnut, and the cap surface is finely velvety or matt rather than lacquered. It generally arises from buried wood so that it looks terrestrial, and its stalk is black and distinctly velvety. Judge on cap colour and surface gloss, and on cap size.

Cerioporus varius (Polyporus leptocephalus). Cap ochre to tan with darker radial fibrillose streaks rather than a uniform deep chestnut, generally smaller and thinner, and, most usefully, the black on the stalk is restricted to the lower portion with a sharp transition to a pale upper stalk. The pores are also a little coarser.

Cerioporus squamosus, the dryads saddle. Enormously bigger, cream to ochre with large flattened brown scales in concentric arrangement, and with angular pores one to two millimetres across that are obvious to the naked eye. Its short lateral stalk has a black crusted base, but nothing else about it matches.

Polyporus tuberaster. Cap covered in small appressed scales and fibrils, stalk pale or only slightly darkened at the base, and it often arises from a hard underground sclerotium.

Coltricia perennis. Terrestrial on soil, especially on burnt or sandy ground, with a velvety concentrically zoned rusty brown cap, brown pores and brown flesh throughout. The brown pore surface and brown flesh separate it instantly.

Lentinus and Neolentinus species. Similar funnel-shaped tough caps on wood, but with true gills, often with toothed edges, instead of pores.

Field checklist

Thin, glossy chestnut, funnel-shaped cap paler at the wavy margin; minute round white decurrent pores at five to eight per millimetre; stalk black and velvety over at least the lower half; thin white tough flesh with no colour change; white spore print; dead hardwood in damp shaded woodland, late spring to autumn.