Goldleaf Shield Identification Guide

A Yellow Stem in the Leaf Litter

You are working through damp broadleaf woodland in late summer, poking around a mossy fallen branch or the edge of an old sawdust pile, and something small and dark catches your eye - a brown-capped mushroom barely 3 cm across. What makes you stop is not the cap but the stipe: a clean chrome-yellow to lemon column, brightest at the base, the sort of yellow that looks almost artificial against dead leaves. That contrast - dull wrinkled brown above, vivid yellow below - is the whole first impression of Pluteus romellii.

Before dealing with the species, settle the genus. Pluteus fruit bodies are saprotrophs on rotting wood; their gills are free, ending in a clean gap around the stipe apex; those gills start white and turn pink as spores ripen; there is no ring and no volva; and the stipe pulls out of the cap cleanly like a ball from a socket. Confirm those four things and the identification problem shrinks to a handful of small brown species.

Reading the Cap

The cap is 1.5-4 cm across, occasionally 5, convex at first and expanding to plane, usually with a low broad umbo. The surface is dry and matt - never viscid, never shiny - and this is the key: over the centre it is finely velvety and distinctly wrinkled, with low ridges and veins radiating and branching across the disc like the surface of crumpled leather. Toward the margin the wrinkling fades and fine radial striations appear when the cap is moist.

Colour runs from dark sepia-brown and olive-brown at the centre to a warmer yellow-brown or ochre-brown toward the edge. The cap is hygrophanous, so a drying specimen pales to dull ochre and loses much of its contrast, which is another reason to examine several fruit bodies of different ages if you can find them.

The Gills

Look under the cap and check attachment carefully - use a hand lens or slice the fruit body vertically. In Pluteus the gills stop short of the stipe entirely, leaving a narrow moat of clear space; nothing is attached, nothing runs down.

The gills themselves are crowded, broad and ventricose (bulging in the middle), white in young fruit bodies and turning a clear salmon or flesh-pink as spores mature. The gill edge is finely fringed under a lens and is often paler than the face, sometimes with a yellowish tinge that echoes the stipe.

The colour change is a timing character: a very young specimen with pure white gills can be mistaken for something else entirely, while an old one is unambiguously pink. When in doubt, look for a second, older fruit body nearby.

The Stipe, and Why It Names the Species

The stipe is 2-5 cm long, 2-5 mm thick, cylindrical or slightly swollen at the base, smooth to finely longitudinally fibrillose, and hollow or narrowly stuffed. Its colour is the diagnostic feature: bright chrome-yellow to lemon-yellow throughout, usually deepest and most saturated in the lower half and at the very base, occasionally paler toward the apex.

There is no ring, no veil zone and no volva. Lift the base intact - the yellow tends to be strongest exactly where a careless pull would break the stipe off, and yellow mycelial threads often cling to the rotten wood below.

Flesh and Colour Change

Split a fruit body lengthwise. The cap flesh is thin and whitish to pale watery brown; the stipe flesh is yellow, matching the surface. There is no colour change on cutting - no blueing, no reddening, no blackening - and the odour and consistency are unremarkable. In this genus the useful information is in the surfaces, not the interior.

Taking and Reading the Spore Print

Set a mature cap gills-down on white card, cover it, and leave it two to six hours. The deposit is pink to pinkish-brown or salmon - one of the most useful spore colours in the whole of mushroom identification, because relatively few genera produce it.

Microscopically the spores are smooth, subglobose to broadly ellipsoid and small, about 6-7.5 by 5.5-6.5 micrometres. The cystidia on the gill faces are thin-walled and roughly sac- or club-shaped, without the thick walls and apical hooks found in Pluteus cervinus and its close relatives - the standard confirmation if you have a microscope.

Substrate, Season and Ecology

Pluteus romellii is a wood-rotting saprotroph, and the wood is usually well decayed and often out of sight: buried twigs and branch fragments, chip and sawdust piles, humus over rotting stumps, and the debris layer under beech, oak, ash, alder and other broadleaves. It rarely grows in numbers - one or two fruit bodies is typical - and it favours damp, shaded, humus-rich spots such as riverbanks and shaded hollows.

Fruiting runs from late spring to late autumn, following rain. Because it depends on decaying wood rather than a living tree partner, the same log or chip pile can produce fruit bodies over several successive seasons until the substrate is exhausted.

Separating the Look-alikes on Morphology Alone

• Pluteus chrysophaeus. The nearest relative and the usual point of argument. Its cap is clearly yellow-brown to ochre-yellow rather than dark sepia, and, crucially, its stipe is whitish to only faintly yellow-tinged. The practical field split is stipe colour: strong chrome-yellow throughout indicates P. romellii.
• Pluteus phlebophorus. Cap dark brown and coarsely wrinkled to net-veined over the whole disc, but the stipe is white or whitish.
• Pluteus leoninus. Larger, with a distinctly golden-yellow cap and a whitish stipe that may be yellow-tinged only at the base - the yellow is in the wrong place.
• Pluteus cervinus. Much bigger, with a fibrillose deer-brown cap and a white stipe streaked with dark fibrils; microscopically its cystidia are thick-walled with two to four apical hooks.
• Pluteus nanus. Small and dark with a finely granulose cap surface and a pale, non-yellow stipe.
• Entoloma species. Also pink-spored, but the gills are attached to the stipe (adnate to sinuate), the build is usually more robust, and the spores are angular in outline.
• Bolbitius titubans. Yellow overall, but the cap is viscid and quickly collapsing, the gills are attached, and the spore print is rust-brown.
• Volvariella. Free gills and a pink print again, but there is a distinct sac-like volva at the stipe base.