Oak bracketPseudoinonotus dryadeus

The oak bracket (Pseudoinonotus dryadeus, formerly Inonotus dryadeus) is a large bracket fungus that sits right at the foot of an old oak or on its roots. It's at its most striking in summer, when young brackets are covered in drops of amber liquid, which First Nature compares to runny honey oozing from set honey. This is guttation: water pushed out by a fast-growing fruit body, and it's why the fungus is also called the weeping polypore. The name dryadeus comes from the dryads, the oak nymphs of Greek myth.

How do you identify oak bracket? Look for a thick cushion or lump with no stem, usually 10 to 30 cm across (up to 40 cm) and 5 to 15 cm thick, often in several tiers. Young brackets are cream, buff or yellowish and finely velvety, with a thick, rounded margin. With age they turn rusty brown, lumpy and pitted where the drops have dried, and finally almost black and cracked. Underneath are tiny pores, 4 to 6 per mm, cream-yellow at first, then ochre and brown. The flesh is yellow-brown to rusty, soft and fibrous when young, then corky. The spore print is pale, whitish to yellowish. Old brackets smell unpleasant.

Where does it grow? Almost always on oak, occasionally on beech, birch, alder or chestnut, and right at the base of the trunk, on the root flare or on surface roots, sometimes a little way from the trunk. Fresh brackets appear from summer to late autumn, mostly from late summer to autumn, and old blackened ones can stay for months, so you may spot them at any time of year.

Is oak bracket edible? No: it's tough, bitter and, when old, smelly. We found no reports of poisoning, but it simply isn't eaten. Extracts have only been tested in the laboratory, and there's no evidence that it treats or prevents any disease.

Is oak bracket dangerous to the tree? It's a parasite that causes a white rot of the roots and trunk base. The decay is hidden in the roots, so a tree can look healthy for years or decline slowly, and it can fail in storms. Often the decay hollows out the centre while the buttress roots stay sound, so the tree stands on them like stilts, which is why tree inspectors call it the Eiffel Tower bracket. It doesn't mean the oak must come down, and there's no effective treatment, but if you find it on an oak near a house, road or path, ask a qualified arborist to assess the tree.

What can you mistake it for? Beefsteak fungus also grows low on oaks, but it's red, tongue- or liver-shaped and bleeds red juice when cut. Chicken of the woods forms bright sulphur-yellow and orange tiers of thin shelves, usually higher up the trunk. Giant polypore and hen of the woods also grow at the base of oaks, but they're made of many thin caps rather than one thick cushion. Artist's bracket is hard and woody, with brown spore dust. Outside our catalogue, the most likely mix-up is the shaggy bracket (Inonotus hispidus): it weeps too, but its surface is hairy and rusty orange, and it grows higher up on trunks and branches, mainly of ash and apple. The lacquered bracket (Ganoderma resinaceum) can sit on oak roots too, but it's hard, with a shiny reddish-brown crust and a reddish-brown spore print.