Franchet's Amanita Identification Guide

First Impression

Franchet's Amanita is a mushroom you notice for its texture before its colour. Walking through warm, dry oak or beech woodland - often on limestone or in Mediterranean holm oak scrub, sometimes under conifers on the same kind of open, sun-warmed ground - you find a medium-sized pale-gilled mushroom whose cap looks as if it has been dusted with mustard powder. The cap is a muted greyish-brown to olive-brown, and standing proud of that dull background is a scattering of soft, crumbly warts in a distinct yellow to ochre-yellow. That contrast - dull cap, yellow warts - is the whole opening argument for the species.

Before naming it, establish the genus. Kneel down and look for the four Amanita signatures: gills that stop short of the stipe and hang free; a white spore deposit; some form of universal veil left behind as warts, patches or a sac at the base; and a partial veil that in most species leaves a skirt-like ring. Then, and only then, dig the whole fruit body out. A trowel matters here, because the base holds half the evidence.

Reading the Cap

The cap runs about 4-10 cm across. It begins hemispherical or egg-shaped, opens through convex to broadly flat, and often keeps a very slight central hump. The ground colour is variable but consistently dull: greyish-brown, olive-brown, drab tan or a faded fawn, usually darker in the centre and paler towards the margin. The surface beneath the warts is dry to slightly tacky in wet weather, not glossy.

The warts are the point. They are the broken remains of the universal veil, and here they are floccose to shortly pyramidal, easily rubbed off with a thumb, and coloured a warm yellow, sulphur-yellow or ochre. In older or rain-washed specimens the yellow leaches towards buff, so look at the warts sheltered near the cap centre and at any that have fallen onto the ground beside the mushroom. On a fresh button they can be dense enough to obscure the cap entirely.

Check the margin with the cap held edge-on against the light. In Franchet's Amanita it is smooth and even, not marked with the radial grooves or fine ridges that some relatives show. That non-striate margin is a real character and it eliminates several yellow-warted candidates immediately.

Gills, Ring and Stipe

Turn the fruit body over. The gills are free - trace one inwards with a fingertip and it stops short of the stipe, leaving a narrow gutter - crowded, moderately broad, and white to cream. Look very closely at the gill edges with a lens: they are often minutely floccose and tinted yellowish, echoing the veil colour, and short intermediate gills of several lengths are interleaved between the full-length ones.

The stipe is 5-12 cm tall, whitish to pale cream, sometimes tinted yellowish where handled, and slightly tapering upwards. Its surface may be minutely fibrillose or slightly scaly below the ring. The ring itself sits high on the stipe, is thin and fragile, hangs as a skirt, and is characteristically flecked or dusted with the same yellow veil material found on the cap - sometimes the yellow shows chiefly on the ring's underside and outer edge. In older specimens the ring may tear away entirely, so a missing ring is not evidence against the name.

The Base - the Diagnostic End

Excavate the base intact. Franchet's Amanita has a firm, rounded to slightly ovoid basal bulb rather than a free membranous sac. Around the top of that bulb and on its shoulders sit irregular concentric rings, ridges or belts of yellowish volval crumbs and scales, matching the warts on the cap. The volva here is adherent and friable, not a loose cup you could tuck a finger into. Brush the soil away carefully with a brush or your fingers instead of washing it, because the crumbly yellow rings wipe off easily.

Flesh, Colour Change and Odour

Slice the fruit body from cap to base. The flesh is white, firm and unmarbled. In some collections it slowly develops a faint pinkish-brown or vinaceous discolouration where cut or where insects have tunnelled, but this is muted and slow rather than the prompt, obvious reddening seen in the Blusher. The odour is mild, faintly fungal, without any raw-potato or radish component.

Taking a Spore Print

Cut the stipe flush against the gills, place the cap gill-side down on paper - use a sheet that is half white and half dark, since a white print is invisible on white - and cover it with a bowl for six to eight hours. Expect a clean white deposit. Microscopically, spores are ellipsoid, roughly 8-10.5 x 5.5-7 um, and importantly they turn blue-grey in Melzer's reagent. That amyloid reaction places the species in section Validae, which is a decisive division: several of the yellow-tinged look-alikes have inamyloid spores and sit in a different section entirely.

Habitat, Partners and Season

The fungus is ectomycorrhizal and lives in partnership with tree roots, so it always appears from soil, never from wood. Its principal partners are oak, evergreen oak and beech, with records under hornbeam, sweet chestnut and, in parts of its range, fir and other conifers. It favours warm, open, often calcareous woodland and Mediterranean scrub, and it is most abundant in southern and central Europe, tailing off northwards. Fruiting runs through summer and autumn, following rain. Fruit bodies appear singly or in small scattered groups.

Separating the Look-alikes

The Blusher (Amanita rubescens). The closest confusion. It has greyish, pinkish or dirty-buff warts rather than yellow ones, and its flesh reddens conspicuously and fairly quickly where cut, bruised or tunnelled by insect grubs - the whole stipe base of an old specimen is often wine-red. Its ring is grooved above and its bulb lacks tidy yellow concentric belts.

Amanita gemmata. Pale yellow to straw-yellow cap with whitish warts - the reverse colour arrangement. Its cap margin is distinctly striate, and its bulb carries a collar-like upturned rim.

Amanita muscaria. Scarlet to orange cap with white warts, a much larger stature and a bulb with neat concentric bands of white scales.

Amanita augusta. A western North American relative with a darker yellow-brown to olive-brown cap and bright yellow warts; it is best separated by range, and by its more strongly yellow-tinged stipe and ring.

Amanita citrina. Uniformly pale lemon or ivory cap with flat whitish veil patches, a large abrupt bulb with a sharp rimmed margin, a non-striate margin, and a distinct raw-potato odour.

Amanita pantherina. Warm brown cap with pure white warts, a strongly striate margin, and a bulb topped by one or two crisp collar-like rings.

Field Checklist

Dull greyish- to olive-brown cap; yellow to ochre warts; non-striate margin; free white gills with yellowish flocked edges; fragile skirt ring flecked yellow; rounded bulb with concentric yellow volval belts; white flesh with at most a slow faint vinaceous stain; white amyloid spore print; broadleaf woodland on warm ground.