Resinous Polypore Identification Guide

First Impression And Setting

The Resinous Polypore looks, when young, more like a soft pad than a bracket. A fresh specimen is plump, watery, velvety to the touch and edged with a broad creamy-white band, and if you press it your thumb sinks in and leaves a dent. That softness is the first surprise, because the mature, dried-out version of the same fungus is stiff and unyielding.

You find it on dead hardwood in autumn, typically in the second half of the season once temperatures drop. Look on fallen logs, standing dead trunks, large stumps and cut ends of maple, beech, birch and oak in deciduous or mixed forest. It frequently fruits in overlapping tiers running along the flank of a log, sometimes for a metre or more, and single caps can also emerge flat against the underside of a trunk.

The overall colour impression at ten paces is a dark brown shelf with a pale rim. Get closer and the interest lies in the details of that rim and in the beads of liquid it carries.

Reading The Cap

Individual caps are 5 to 25 cm wide and 1 to 3 cm thick, semicircular, fan-shaped or shell-shaped, broadly attached to the wood with no stalk. Where several fuse they form long undulating shelves.

Texture first. Young caps are finely velvety or softly tomentose — brush the surface and it feels like short suede or moleskin. With age this velvet wears away, particularly toward the attachment point, leaving a smoother and eventually somewhat wrinkled or roughened surface.

Colour is arranged in concentric zones running parallel to the edge. The growing margin is white to cream or pale buff, sometimes tinged pinkish; behind it lie bands of ochre, rust, tan and cinnamon, deepening inward to dark reddish-brown, chocolate and nearly black at the point of attachment. Old caps darken overall and the pale margin is lost, so the two-tone appearance is a character of actively growing material.

Now look for droplets. On fresh, well-hydrated specimens, small clear to amber-yellow beads of liquid stand on the upper surface and along the margin. They dry to shiny resinous spots that can stain the surface darker. Their presence is a strong supporting character; their absence in dry weather proves nothing.

Reading The Pore Surface

Turn the bracket over or duck under the log. The underside is a flat poroid surface, white to cream or very pale buff when fresh.

Press it firmly. The surface bruises to brown, greyish-brown or dull rust within a minute, and the bruise persists — you can write on it. Older or drier specimens go a dingy buff to greyish-brown all over without help.

With a hand lens, the pores are tiny, round to slightly angular, and number roughly 4 to 6 per millimetre. The tube layer is short, usually 3 to 8 mm deep, and forms a single stratum sitting under the flesh — cut vertically and you will see one clean band of tubes, not stacked layers.

Flesh, Section And Colour Change

Cut a fresh bracket vertically with a knife. The cut should be easy in fresh material — the blade goes through as if through a firm sponge, and liquid may bead at the cut face.

The flesh is 5 to 25 mm thick, pale buff to pinkish-tan or watery cream, soft, moist and slightly fibrous, and it is usually faintly zoned. Above the flesh, just under the surface tomentum, there is often a thin darker line, and a section through an old bracket shows the whole structure gone hard, dark and horny.

The change with age is dramatic and worth remembering, because young and old collections look like different organisms. Fresh: soft, wet, pliable, pale-margined, light in the hand. Old: rigid, dark brown to black, dry, light and brittle, with a dull greyish pore surface. Dried brackets persist on logs through winter.

Odour is mild and faintly sweetish or slightly resinous, useful as a supporting impression rather than a decisive character.

Taking A Spore Print

Cut a piece of bracket with an intact tube layer and lay it pore-side down on black paper, since the deposit here is pale and will vanish on white. Cover with a bowl to hold humidity and leave six to twelve hours; a fresh, actively growing specimen prints readily, a dried-out one may not print at all.

The deposit is white to very pale cream. That pale print, combined with a brown-topped bracket on hardwood, cleanly separates the species from the many brown-spored crust and bracket fungi. In the field you can sometimes see the white dust settled on foliage or on lower brackets in a tiered colony.

Substrate, Season And Ecology

This is a saprotrophic wood decayer working almost exclusively on hardwoods — maple, beech, birch, oak, cherry and similar broadleaved trees. It causes a white rot, removing lignin as well as cellulose and leaving decayed wood pale, soft, fibrous and easily crumbled between the fingers. It typically colonises wood that is already dead, appearing on logs in the middle stages of decay rather than on freshly fallen or fully rotted material.

Fruiting is annual, with a distinctly late season: most collections come from mid-autumn into early winter, often continuing after the first frosts when many other polypores have finished. The brackets do not add tube layers in later years, though the blackened remains hang on and can confuse a spring survey.

Because it works on standing dead trunks and large fallen logs, it is a significant recycler of coarse woody debris in temperate deciduous forest, and its rotted wood becomes habitat for invertebrates and later colonisers.

Separating It From Look-alikes On Morphology

Ischnoderma benzoinum. The closest relative and the hardest call. It fruits on conifers rather than hardwoods, tends to be darker overall with a blacker crust in age, and often has a narrower pale margin. Host wood is the practical separator: check whether the log has needles, resin canals and a straight-grained conifer look, or the dense, ring-porous character of a hardwood.

Bjerkandera adusta. Superficially similar thin grey-brown brackets on hardwood, but the pore surface is smoky grey to nearly black rather than white, and a vertical section shows a thin dark line between the pale flesh and the tubes. Its brackets are much thinner and never plump and watery.

Fomitopsis and other perennial brackets. Hard and woody from the outset, with a crusted zoned upper surface and, in section, multiple stacked tube layers from successive seasons. The Resinous Polypore has one tube layer and is soft when fresh.

Ganoderma applanatum. Perennial, with a dull hard grey-brown crust, dark chocolate flesh often containing white chalky flecks, and a brown spore deposit that coats everything below it. Its pore surface also bruises brown, so rely on the crust, layered tubes and print colour.

Ganoderma lucidum group. Hard, shell-like and varnished with a glossy mahogany crust, plus a brown print — unmistakably different from a soft velvety brown bracket.

Inonotus and Phellinus species. Their flesh is rusty to yellow-brown rather than pale buff, and it usually darkens dramatically in a drop of alkali; many are hard, hoof-shaped or perennial.

Trametes species. Thin, tough, leathery, strongly zoned and often hairy, with white flesh but a distinctly flat, flexible bracket rather than a thick watery pad.

A Quick Field Sequence

1. Soft, plump, velvety bracket on a hardwood log or stump, autumn.
2. Upper surface zoned rust to chocolate-brown with a broad white to cream growing margin.
3. Clear to amber droplets on the surface of fresh specimens.
4. Underside white to cream, bruising brown, 4 to 6 tiny pores per millimetre.
5. Section shows soft pale buff flesh over a single short tube layer.
6. Spore print white on black paper; old brackets go hard, dark and brittle.