Gemmed Amanita Identification Guide

First Impression

Gemmed Amanita is a pale, quietly handsome mushroom that turns up on light, sandy or gravelly ground under conifers - coastal pine, montane Douglas-fir, sandy heathland pine plantations - and also under oak on similar poor soils. On the west coast of North America it is a signature fungus of spring, fruiting after the winter rains, while in Europe and eastern North America it is more usually a summer and autumn species.

What you see first is a smooth, warm straw-yellow to buff dome sitting on a slender white stalk, with a few flat whitish patches lying on the cap like scraps of tissue paper. The overall tone is pale butter, honey or pale apricot rather than the vivid orange-scarlet of the Fly Agaric. Fruit bodies are usually solitary or in small loose scatters, pushing through needle litter or sand.

Establishing the Genus

Run the Amanita checks before anything else: free gills, a white spore deposit, a partial veil leaving a ring on the stipe, and universal veil tissue left as patches on the cap and something structured at the base. Then excavate the entire fruit body. Half the diagnostic information in this species is below ground, and a specimen snapped off at soil level is nearly unnameable.

Reading the Cap

The cap measures 3-10 cm across, occasionally to 12. It starts hemispherical or egg-shaped and expands through convex to broadly flat, sometimes with a very low central hump. Colour is pale yellow, straw, cream-buff or warm honey, generally a little deeper in the centre and paler outwards; it fades noticeably in sun and rain, so a bleached specimen can look almost white at the margin.

The surface is viscid when moist - run a dry fingertip across it in damp weather and it drags slightly - and dries to a low satin sheen with adhering needles and grit.

The universal veil remnants are flattish, thin, felty white to cream patches rather than pointed cones. They are usually few, sometimes only two or three, and heavy rain removes them completely. Do not reject the name because a specimen is bald; check the ground beside it for the fallen patch.

Then read the margin edge-on. In Gemmed Amanita the outer 5-10 mm is short-striate - marked with fine radial grooves corresponding to the gills beneath - though the striation is often subtler than in a Panther Cap and can be almost absent in young buttons. Combined with the pale cap and white patches, it is a helpful pointer.

Gills, Ring and Stipe

The gills are free from the stipe, crowded, moderately broad, and white to very pale cream, with short intermediate gills interleaved. Edges are even to minutely floccose.

The stipe is 5-12 cm tall and 1-2 cm thick, white to pale cream, sometimes with a faint yellowish blush, and slightly club-shaped, thickening gradually towards the base. Its surface may be smooth, silky-fibrillose, or finely scurfy above.

The ring hangs high on the stipe as a thin, delicate, white membranous skirt. It is fragile - often collapsing against the stipe as a fibrous zone, and sometimes vanishing altogether in older specimens - so treat its absence as neutral rather than as evidence against the name.

The Base - the Collared Bulb

Dig carefully with a trowel and clean the base with a brush rather than water. Gemmed Amanita has a rounded to ovoid or slightly turnip-shaped basal bulb, and around its upper margin sits a narrow, free, upturned rim of volval tissue: a shallow collar that stands slightly away from the stipe, like the lip of a small cup. Sometimes this rim is accompanied by one or two additional low ridges or belts of veil material on the bulb below it.

Cut the base lengthwise to see the collar in section. It is not a deep, loose membranous sac in which a finger could be inserted, and it is not a sharp abrupt rim that overhangs the bulb like a saucer edge. That intermediate structure - a small upturned collar on a rounded bulb - is one of the most reliable features of the species.

Flesh, Odour and Colour Change

Split a fruit body from cap to base. The flesh is white, soft, and unchanging: it does not redden, blue, brown or stain over twenty minutes of watching, and it is often faintly yellowish just beneath the cap cuticle. The odour is mild to slightly fungal. It has none of the raw-potato or radish smell characteristic of Amanita citrina, and that absence is diagnostically useful.

Taking a Spore Print

Cut the stipe flush with the gills, lay the cap gill-side down across a sheet that is half white and half black, cover with a bowl, and leave for six to eight hours. The print is white. Under a microscope the spores are broadly ellipsoid, about 8-11 x 6.5-8 um, and inamyloid - they do not stain blue-grey in Melzer's reagent. That non-reaction is the key laboratory character, placing the species in section Amanita with the Fly Agaric and Panther Cap, and separating it from A. citrina and the Blusher, which are amyloid.

Habitat, Partners and Season

The species is ectomycorrhizal and grows from soil, never from wood. It is most strongly associated with conifers - pines, spruce and Douglas-fir - and is also found with oak, birch and other hardwoods, with a marked preference for poor, sandy, gravelly or otherwise well-drained acidic ground. Coastal dune pine, heathland, sandy plantations and montane forest are all typical settings.

It is widespread in Europe and across North America, forming a complex of closely similar taxa rather than one tidy species. Fruiting is in spring on the North American west coast and in summer to autumn elsewhere.

Separating the Look-alikes

Amanita muscaria var. guessowii. Yellow to orange cap with white warts, but substantially larger and more robust, with a non-striate or only shortly striate margin and a bulb encircled by several concentric bands of shaggy white scales rather than one clean collar.

Amanita citrina. Pale lemon or ivory cap with flat whitish or brownish patches, a smooth non-striate margin, a distinctly large and abruptly rimmed bulb with a sharp overhanging edge, a strong raw-potato odour, and amyloid spores.

Amanita pantherina. Warm brown to dark hazel cap with crisp pure white warts, a strongly grooved margin, and a bulb topped by one or two sharp collar-like rings. Cap colour is the quickest separator.

Amanita franchetii. Yellow to ochre warts on a dull greyish-brown cap - effectively the inverse colour scheme - with a non-striate margin, a yellow-flecked ring, and amyloid spores.

Amanita aprica. A western North American spring species with a yellow cap whose veil remnants are appressed and adhere tightly, often leaving the surface looking painted rather than patched.

Amanita crenulata. Smaller and duller, with powdery grey-tinged veil remnants and a less defined bulb.

Field Checklist

Pale straw to honey-buff viscid cap; a few flat white veil patches; short-striate margin; free white gills; slender white slightly clubbed stipe; fragile high white skirt ring; rounded bulb with a narrow upturned collar; white unchanging flesh with no potato odour; white inamyloid spore print; sandy acid soil under conifers or oak.