Native Bread Identification Guide

Two Very Different Things to Recognise

Laccocephalum mylittae is unusual because it presents in two completely different forms, and most people meet only one of them. Underground it forms a large, hard, tuber-like sclerotium, a compacted mass of fungal tissue that can persist for years. Above ground, after the right conditions, it produces a stalked polypore that grows directly out of that sclerotium.

So the identification runs on two tracks. Either you have turned up a dense buried lump while digging and are asking what it is, or you are standing over a small tan bracket fungus on a stalk in eucalypt woodland and have noticed that the stalk goes down into the soil rather than into a log.

The Setting

This is an Australian fungus of dry sclerophyll forest and woodland, recorded from Victoria, Tasmania, New South Wales, South Australia and Western Australia. The habitat is eucalypt-dominated, often with a hard, gritty soil full of buried dead roots and fragments of old timber.

Fruiting is famously associated with disturbance, particularly with fire, and with soaking rain afterwards. Autumn and winter, after the ground has been thoroughly wetted, is the usual window. Sclerotia, by contrast, can be encountered at any time of year because they sit in the soil waiting.

Reading the Sclerotium

If you have the underground stage, work through it carefully.

Size and shape: irregularly rounded, ovoid or elongate, commonly 3 to 15 cm and occasionally to 30 cm or more, and surprisingly heavy for its size. The dense, pale, loaf-like mass is the origin of the common name.

Outer surface: a thin, hard, dark brown to black rind, often knobbly, sometimes with soil and sand grains cemented into it and with old root fragments protruding.

Interior: this is the decisive check. Cut it in half. The inside is white to cream, extremely dense and firm, and marbled with fine darker lines and veins that wander through the tissue. It is homogeneous fungal material, not layered, and it holds together like a hard cheese rather than crumbling.

What it is not: there is no vascular ring as in a plant tuber, no concentric annual rings as in a woody gall, no fibrous strands as in a root, and no internal cavity or spore mass as in a hypogeous fungus.

Reading the Fruit Body

When it fruits, the sclerotium sends up a stalked polypore.

Stipe: 3 to 15 cm long, up to about 1.5 cm thick, central to slightly off-centre, pale ochre to buff or brownish, often finely velvety or minutely scurfy, and continuing downward as a rooting section that leads to the sclerotium. Excavate carefully with your fingers and follow it down; the connection is the single best character in the field.

Cap: 3 to 15 cm across, circular in outline, at first convex and quickly becoming flattened, depressed at the centre and finally funnel-shaped. The surface is pale tan, ochre-brown to greyish brown, dry, smooth to finely fibrillose, sometimes minutely scaly toward the disc, and often radially wrinkled with age. The margin is thin, incurved when young, paler than the disc and sometimes wavy or lobed.

Pore surface: white to cream, ageing to buff. The tubes are shallow, a millimetre or two deep, and run decurrently down the upper stipe. Pores are small and angular, roughly 2 to 4 per millimetre, sometimes elongating radially near the stipe. Press a fingertip into them; they are firm and do not stain.

Flesh: white, tough, fibrous and dry, thin relative to the cap width, and unchanging when cut. This is a leathery polypore, not a soft fleshy mushroom.

Taking a Spore Print

Cut the cap free and lay it pore surface down on black card, covered, for six to twelve hours. Old or weathered fruit bodies frequently yield nothing, so choose one that is fresh and firm with a clean white pore layer.

The print is white. Under the microscope the spores are hyaline, smooth, thin-walled, cylindrical to narrowly ellipsoid, and do not react in Melzer reagent. The white print rules out the brown-spored crust and bracket fungi that share the habitat.

Substrate and Ecology

The fungus is a decomposer of buried dead wood, especially eucalypt roots and stumps below ground. The sclerotium functions as a long-term storage body: the mycelium accumulates reserves within a rind-protected mass, sits out drought, and then converts those reserves into a fruit body when a wet season, often following fire, gives the right cue. That is why fruit bodies appear apparently from bare soil, with no visible log anywhere near.

Separating the Look-Alikes on Morphology

Other Laccocephalum species. These are the closest relatives and all share the sclerotium habit, so getting to genus is easy and the work is at species level. Separate them on pore size and shape, cap colour and surface texture, stipe proportions and how strongly the cap becomes funnel-shaped. Take careful notes and photographs of the pore layer at scale, because that is where the distinctions sit.

Stalked surface polypores such as Polyporus arcularius and P. brumalis. Both are centrally stalked with a depressed cap, so from above they can look almost identical. The difference is what is below: they arise from wood lying on or above the ground, with no sclerotium. P. arcularius also has conspicuously large, angular, elongated pores and a hairy cap margin; P. brumalis has smaller round pores and a smoother cap.

Pisolithus species. A buried-based, loaf-like body on a stalk-like rooting base can suggest this fungus, but a cut Pisolithus shows a mass of small pea-like chambers in a jelly matrix and eventually collapses into ochre-brown spore powder. There is no pore layer and no firm white marbled interior.

Native truffle-like fungi such as Mesophellia, Castoreum and Hysterangium. These are also found as buried rounded bodies. Cut them open: they contain a spore mass or gleba, often chambered, marbled with sterile veins or built around a distinct central core, and they change texture and colour as they mature. A Laccocephalum sclerotium remains solid white tissue with fine dark veining and never develops a powdery or waxy spore mass.

Plant tubers, lignotubers and burls. Cut surfaces show plant anatomy: rings, radiating rays, vascular tissue, fibres and often bark. The sclerotium shows none of these.

The working test in the field is therefore simple. Follow the stalk downward. A stalked, white-pored, tough tan polypore that is physically attached to a hard black-rinded underground mass with dense white marbled tissue inside is Laccocephalum mylittae.