Cortinarius gentilis Identification Guide

The Setting and the First Impression

Picture a spruce or pine forest on acid ground in late autumn: a deep carpet of feather moss and sphagnum, bilberry stems, wet needles, and the hummocky ground at the edge of a bog. In among the moss stand small, slender, tawny mushrooms, singly or in twos and threes, on stems that look too long and thin for the caps they carry. From above, each cap is a warm ochre-yellow to foxy tan with a sharply pointed peak.

Two things register at once. First, the fruit body is small and delicate rather than fleshy - this is not one of the stout ochre webcaps of limestone spruce forest. Second, if you crouch and look at the stem in good light, you can see one or more bright yellow bands wrapped round it, standing out against the browner ground colour of the stipe. That yellow banding on a slender tawny mushroom in mossy conifer woodland is the core of the identification.

Establishing the Genus

Get to Cortinarius before you get to species. Look at a young unopened specimen: a cobwebby veil of fine silky fibres, the cortina, stretches from the cap margin to the stipe, and it looks exactly like a torn scrap of spider web. It never becomes a membranous ring. On older fruit bodies the cortina has collapsed onto the stem, where rust-brown spores settle on it and stain it into a faint rusty zone or fibrillose girdle.

Confirm with the gills: in a maturing webcap they move steadily toward rust-cinnamon, and the spore deposit is rust-brown. A slender mossland mushroom with a cobweb veil and rusty gills is a webcap, which reduces the field considerably even though the genus is enormous.

Reading the Cap

The cap is small, 1.5 to 4 centimetres across and occasionally to 5. Its shape is one of the better characters: conical or bell-shaped when young and expanding to convex or broadly conical, but almost always retaining a distinct, often sharp and prominent umbo at the centre. That pointed peak on a small cap gives the species a characteristic silhouette against the moss.

The surface is dry - never viscid or greasy, even in rain - and matt to finely silky-fibrillose, sometimes minutely scurfy over the disc. It is hygrophanous: moist caps are a saturated tawny-orange, ochre-yellow, foxy brown or warm rusty tan, and drying caps fade to a paler yellow-ochre or dull straw, often from the centre outwards or in blotchy patches. Very young caps frequently carry small yellowish veil fibrils along the margin, remnants of the universal veil.

Gills, Stipe and Veil

Turn one over. The gills are the second good character: distinctly distant, thick and rather narrow, adnate to slightly notched at the stipe, and few in number compared with most small brown mushrooms of this size. You can count them easily. Colour begins as a warm saffron-ochre or yellow-brown, sometimes with an orange tone, and matures through cinnamon to deep rust-brown as the spores ripen. The edges tend to remain slightly paler and are often minutely uneven.

Now the stipe, which carries the best character of all. It is 3 to 8 centimetres long and only 3 to 6 millimetres thick, cylindrical, often slightly flexuous or tapering downward, hollow with age, and coloured tawny to ochre-brown with a paler yellowish apex. Around it, arranged as one to three irregular girdles or as scattered fibrillose patches, are remnants of the universal veil - and those remnants are a distinct chrome to sulphur-yellow. This is the point people miss: the veil is yellow, not white, and against a brown stipe the bands are conspicuous once you know to look. In moss the base is often surrounded by yellow-tinted mycelial threads binding the substrate.

Flesh, Colour Change and Odour

Slice a fruit body from cap centre to stipe base. The flesh is thin, watery, and coloured yellowish, ochre or pale brown - it is not white. There is no bruising reaction worth the name: no bluing, no reddening, no blackening, and no latex. The stipe flesh may be a shade more yellow in the cortex where the veil sits.

Odour is faint. Most collections smell weakly earthy or slightly radish-like, and some observers report a faint iodine-like note when the flesh is dried; nothing strong or diagnostic.

Taking a Spore Print

Cut the cap free and lay it gills down on white paper under a cup for four to six hours. The deposit is rust-brown to ochre-rust, quite unmistakable against white. Because the fruit bodies are small, use two or three caps together to get a thick enough scatter to judge.

Under the microscope the spores are ellipsoid to almond-shaped, coarsely warted, and around 7 to 9.5 by 5.5 to 7 micrometres. There are no conspicuous gill-edge cystidia to work with, so identification within this section rests mostly on macroscopic characters and habitat.

Substrate, Partners and Season

Cortinarius gentilis is mycorrhizal, partnering conifers - spruce and pine above all - and it is tied to acid, nutrient-poor, often damp ground. The productive places are boreal and montane conifer forest, mossy plantation floors, bilberry and heather understorey, and the drier hummocks and margins of sphagnum bogs. It does not grow on wood, on rich lowland soil, or with broadleaf trees.

Fruiting runs from late summer into late autumn, peaking in September and October in northern Europe, and it is a species you find as scattered individuals or small groups rather than in troops. Because it is small and its colours match the litter, it rewards slow searching with your eyes at ground level.

Separating It From the Look-alikes

Cortinarius rubellus, met in older books as Cortinarius speciosissimus, is the nearest thing and shares the conifer and sphagnum habitat and the yellow veil bands. Separate on size and colour: rubellus is a distinctly larger and stouter mushroom with a cap 3 to 8 centimetres across, coloured a stronger foxy orange-red to brick or rusty orange, with a more felted or scurfy cap surface and a thicker stipe. Cortinarius gentilis is smaller, more slender, more yellow-ochre than red, with a proportionally longer thin stem. If you have both in front of you the difference is obvious; from a single specimen, measure the cap and the stipe thickness before deciding.

Cortinarius orellanus is larger again, has a dry foxy-orange minutely scaly cap, lacks distinct yellow veil girdles on the stipe, and grows in broadleaf woodland with oak and beech on warmer, often calcareous ground - a different habitat altogether.

Cortinarius cinnamomeus and Cortinarius croceus are the dermocyboid species most often confused with it. Both have far more crowded gills - crowded rather than distant - coloured bright saffron-yellow, golden or olive-yellow, and their caps are more olive-brown to cinnamon and less sharply umbonate. Their stipes are yellow-fibrillose overall rather than carrying discrete girdles. Gill spacing plus gill colour splits them from gentilis quickly.

Cortinarius limonius is larger, brighter orange-yellow, and stouter, with a more fleshy cap. Cortinarius malicorius has olive-yellow gills and an orange veil.

Outside the genus, Galerina marginata is a small brown mushroom with a rusty print on rotten conifer wood, but it grows on wood, has a smooth greasy hygrophanous cap and a true membranous ring rather than a cobweb veil. Gymnopilus species also have rusty prints but grow on wood, are brighter yellow and have crowded gills. Small Hebeloma and Inocybe species have clay-brown or dull brown prints and are readily separated by print colour alone.

The Short Version

Small slender fruit body; dry, hygrophanous tawny to ochre-yellow cap with a sharp umbo; distant thick gills going saffron to rust; a thin tawny stipe wearing one to three bright yellow veil girdles; yellowish-brown flesh with no colour change; rust-brown spore print; moss and sphagnum under spruce or pine on acid ground in autumn. Check the stipe for yellow bands and count the gills, and the identification comes together fast.