Galerina marginata Identification Guide

What the Name Now Covers

Before working through the characters it helps to know that Galerina marginata as currently understood is a broad concept. Several names that older books treated as separate species, including collections once called Galerina autumnalis, Galerina oregonensis, Galerina venenata and Galerina unicolor, are now folded into one variable species. The practical consequence for identification is that you should expect variation in cap viscidity, ring persistence and substrate preference within a single taxon, and that matching an old illustration exactly is neither necessary nor sufficient.

Habit and Stature

The fruit bodies are small to medium and modestly built: caps typically one and a half to four centimetres, occasionally reaching six, on slim stems. They occur singly, in scattered groups, or in loose to fairly dense clusters where several stems rise from a common patch of colonised wood. The overall silhouette is a rounded bell on a straight stalk, and the proportions stay slender rather than becoming squat.

Always begin by resolving the attachment. Follow each stem down through moss and litter to its origin. This species colonises wood and only wood, so the base will end on a log, a stump, a branch fragment, a wood-chip flake or a buried root. Fruit bodies emerging from apparently bare ground are common and simply mean the wood is out of sight.

The Stipe, Ring and Base

Taking the stem first is a useful discipline here, because it carries the most stable characters. It is two to six centimetres long, three to eight millimetres thick, equal or very slightly swollen below, and becomes hollow as it matures. A membranous ring sits high on the stem in young material. It is thin and easily destroyed, so in weathered collections it survives only as a fibrillose girdle or a faint line where spores have collected, and its total absence in old fruit bodies should not be treated as evidence against the species when younger neighbours show it.

The two zones of the stem differ. Above the ring, the surface is pale ochre or buff and finely pruinose, looking dusted under a lens. Below the ring, the ground is brown and grows progressively darker toward the base, and it is overlaid with flattened whitish silky fibrils that produce a faint streaked, frosted or watermarked appearance. Run a fingernail along it: the covering is smooth and appressed, with no coarse projecting scales. White mycelial down usually mats the extreme base to the wood.

The Cap Through Its Weather Cycle

The cap is smooth and bald, without scales, and only slightly tacky in wet weather. It begins convex or bluntly conical, expands to broadly bell-shaped, and finally becomes almost flat with a persistent low umbo. The margin is often faintly wavy or upturned in old fruit bodies.

What makes cap colour confusing is hygrophany. Saturated caps are a warm tawny honey-brown to cinnamon or dull orange-brown, and the outermost few millimetres of the margin are translucent-striate: the gill lines show through the flesh as fine radial shadows. When the cap dries it pales from the disc outward through ochre to buff, and a partly dried cap shows an irregular dark rim against a pale centre. It follows that two fruit bodies twenty centimetres apart on the same log can look like different species. Record the wet colour and the drying pattern as separate observations.

The Gills

Gills are close, moderately broad, and attached to the stem squarely or with a slight tooth that runs a short distance downward. In young fruit bodies they are pale ochre-yellow or dull buff. Maturation carries them through tan to a warm rusty cinnamon-brown, and the ripening colour drifts onto the stem, dusting the veil zone rust. Gill edges are slightly paler and, under a lens, minutely fringed. Comparing several ages within a single collection gives a much stronger picture than describing one cap.

Flesh, Odour and Reaction to Cutting

Split a fruit body longitudinally. The flesh is thin, watery and pale brownish, more strongly coloured in the stem than the cap, and it does not stain blue, green, red or black on exposure. Any colour development is limited to slow browning along the cut edge as the tissue dries. The odour is faintly farinaceous in some collections and essentially absent in others, so it is a supporting note rather than a decisive character.

The Spore Print and What Follows It

Make the print from a fully mature cap: stem cut flush, cap gill-down on white paper, covered, several hours in a cool place. The deposit is rusty brown to ochre-brown. That single observation removes the white-spored wood mushrooms, the purple-brown-spored group and the very dark-spored group from consideration in one step.

Microscopy then does the real work. The spores are ellipsoid to almond-shaped, about eight to eleven by five to six and a half microns, with a distinctly roughened, wrinkled or warty outer wall that frequently loosens or partly detaches. Near the point of attachment there is a smooth suprahilar patch, the plage, visible as a flat clear window in the ornamentation. A germ pore is absent or indistinct. In Melzer's reagent the spores turn reddish-brown, which is to say they are dextrinoid. On the gill edges you will find abundant cheilocystidia, flask-shaped with a swollen base and a narrowed neck. Taken together, roughened dextrinoid spores with a plage plus flask-shaped cheilocystidia constitute a determination that no external character can match for certainty.

Substrate, Season and Ecology

This is a saprotrophic wood decomposer, causing a brown rot in the wood it colonises. Conifer logs and stumps in an advanced state of decay are the most frequent hosts across much of its range, with spruce, pine, fir and hemlock all recorded, but hardwood and landscaping wood chips are used as well. It is widespread in the northern temperate zone and has been reported far beyond it.

Season is unusually long. Fruiting can begin in spring, continue sporadically through wet summer spells, peak in autumn, and persist into cold weather after many other wood-rotters have finished. Cool, wet conditions with a well-soaked substrate produce the heaviest flushes, and the same log will fruit repeatedly across several years.

Working Through the Look-Alikes

Kuehneromyces mutabilis is the closest morphological match and the one to resolve first. It clusters more tightly, favours hardwood stumps, and shows a sharply two-toned cap with a darker moist marginal zone. The decisive difference is on the stem below the ring, which in Kuehneromyces bears distinct dark brown recurved scales rather than flat silky fibrils. Its spores are smooth, with an obvious germ pore and no plage.

Armillaria species have a ring on a stem on wood, but are larger and coarser, with fibrous scaly caps, a thicker persistent ring, whitish gills and a white spore print. Hypholoma species form dense tufts, show yellow to olive-green tints in the gills and give a purple-brown print. Pholiota species are larger and typically slimy or shaggily scaly. Flammulina velutipes has a smooth orange, viscid cap, a velvety dark brown stem, no ring at all, and a white print. Gymnopilus species are larger and brighter orange-rust, often with a coarser cap surface and, in many species, no well-formed membranous ring. Ringed Pholiotina and Conocybe species are fragile, thin-fleshed, and grow on soil, dung or lawns rather than wood, with smooth germ-pored spores.

Condensed Field Sequence

Confirm wood attachment; note habit and cluster form; check for a ring or its remnant; examine the stem below the ring for appressed silky fibrils on a darkening brown ground; describe the cap wet and dry, noting translucent striations; follow the gill colour through the collection; take a rusty brown print; confirm roughened dextrinoid spores with a plage and flask-shaped cheilocystidia.