Lumpy Bracket

The Lumpy Bracket is the heavyweight of the genus Trametes. Where most of its relatives are thin, flexible fans, this species produces a solid, corky bracket several centimetres thick with a conspicuous swelling — the 'lump' — where it joins the wood. Fresh specimens are strikingly pale, almost chalk-white, and only gradually pick up buff and grey tones and the near-universal coating of green algae.

Its second defining feature is the pore surface. Instead of the small round pores typical of Trametes, the tubes here are stretched radially into long slots, so that the underside reads as a series of fine parallel grooves running outward from the attachment. In older or well-developed specimens these slots divide and merge into a shallow maze, which is why the species is sometimes mistaken for one of the true mazegills.

It is closely tied to beech across much of its range and is one of the standard fungi of beech stump surveys in European woodland.

Cap

The bracket is 5-20 cm wide and 2-6 cm thick, semicircular to broadly fan-shaped, and conspicuously convex and swollen just behind the margin where it attaches — the lump that gives the species its name. The upper surface is uneven and slightly bumpy, finely velvety at first and later smooth, whitish to cream when fresh, ageing pale grey or buff and very often entirely green with algae. Concentric zoning is present but faint, expressed mainly as low ridges.

Pores

The pore surface is white to cream, ageing pale straw. Pores are markedly elongated radially, forming slots roughly 1-2 mm long and about 1-2 per millimetre across, often branching and joining into a shallow labyrinth toward the base while remaining more slot-like near the margin. The tube layer is 3-10 mm deep.

Flesh & spore print

The context is white, thick, corky and firm, retaining its pale colour throughout. The bracket is stalkless and broadly attached. The spore print is white, from smooth cylindrical spores.

Lumpy Bracket fruits on the stumps and fallen trunks of broadleaved trees, with beech overwhelmingly the favourite host. Hornbeam, birch, lime, poplar, oak and other hardwoods are also used. It characteristically appears on the cut surfaces and upper faces of large stumps in managed woodland and parkland, often several brackets in a tier along one edge.

It is widespread across Europe and temperate Asia and has established in parts of North America. Fruit bodies begin developing in summer and mature through autumn, but the thick corky brackets persist through winter and often for a second season, greying and hardening as they age.

This species is a saprotroph producing a white rot, degrading both lignin and cellulose and reducing dense hardwood to a pale, soft, fibrous condition. Its preference for large beech stumps makes it a familiar agent in the slow breakdown of felled timber in worked woodland.

Because it produces thick, long-lived fruit bodies it invests heavily in each bracket and reuses the same substrate for several years, extending its mycelium deep into the stump. There are reports of it colonising wood already occupied by other bracket fungi, and the sharp dark demarcation lines visible in a sectioned stump mark where its mycelium meets a competitor. The rotted wood it leaves behind holds moisture well and becomes a seedbed for mosses and tree seedlings.

Daedalea quercina, the Oak Mazegill, has a genuinely maze-like, thick-walled pore surface and a duller brownish-buff to grey-brown colour, is even more corky, and grows on oak rather than beech. Daedaleopsis confragosa is thinner, browner and reddish-zoned above, and its pale pore surface flushes pinkish-red where bruised, which the Lumpy Bracket never does.

Lenzites betulinus has true radiating gill plates rather than elongated pores, and is a thinner, hairier bracket. Trametes versicolor and Trametes hirsuta are both far thinner and more flexible with small round pores. The whitish Trametes pubescens lacks the basal hump and has round pores.