Grey Veiled Amanita
Amanita porphyria
Also called porphyry amanita, grey veiled amanita
A conifer-loving amanita with a smooth greyish-brown cap washed with purple, a grey membranous ring, and an abrupt rounded bulb finished with a sharp rim.
Overview
Amanita porphyria is a medium-sized amanita of northern conifer forests, named for the porphyry-like purplish cast that tints its otherwise grey-brown cap. It is a comparatively slender, sober species, easily passed over, but a careful look at its ring and bulb makes it one of the more clearly defined members of the genus.
It belongs to the group of amanitas with amyloid spores and a bulbous base, close to Amanita citrina and Amanita brunnescens. In fact, the three share the same basic architecture: a smooth non-grooved cap, a membranous ring, and an abrupt, rounded, rimmed bulb, differing mainly in colour and in whether the flesh discolours.
Field guides consistently highlight two characters: the grey rather than white ring, which is unusual in the genus, and the strong raw-potato smell of fresh flesh.
How to identify it
Cap
4-10 cm across, convex then flat, sometimes slightly umbonate. Colour is greyish brown to smoky brown with a distinct violet, lilac, or purplish sheen, especially when moist, and the surface is smooth and slightly greasy. Flat greyish veil patches may be present but frequently wash away entirely, leaving a bare cap. The margin is smooth, not grooved.
Gills
Free, crowded, white to slightly greyish-cream, narrow. Short gills are truncate and evenly interspersed.
Stipe
6-12 cm long, slender, whitish to pale grey and often marked with grey fibrils or a faint purplish-grey pattern above the bulb. The ring is membranous, pendulous, and distinctly grey, at least on its underside, which is a strong character. The base ends abruptly in a rounded, almost spherical bulb with a sharp, well-defined rim or collar at its top edge.
Flesh and spore print
Flesh white, sometimes greyish under the cap skin, unchanging when cut. Odour distinctly of raw potato or fresh turnip. Spore print white; spores are globose and amyloid.
Where and when it grows
This species is strongly associated with conifers, especially Norway spruce, Scots pine, and other pines, and grows on sandy, acidic, often nutrient-poor soils in mossy coniferous woodland. It occasionally occurs under birch in mixed stands.
Its range covers northern and central Europe, Scandinavia in particular, extending across boreal Eurasia, and it is also recorded from northern and montane North America. Fruiting runs from late summer into autumn, typically August to October, with fruit bodies appearing singly or in scattered groups in moss and needle litter.
Ecological role
Amanita porphyria is an ectomycorrhizal partner of conifers. Its hyphae sheathe spruce and pine root tips and form the Hartig net between root cells, supplying the tree with water, nitrogen, and phosphorus scavenged from nutrient-poor podzolic soils in return for photosynthetic carbon.
Because it favours acidic, sandy, low-fertility ground, it is a characteristic member of boreal and heathland conifer communities. Its perennial mycelium persists among the mossy needle litter, and fruit bodies appear in the same locations year after year once a partnership with a given stand of trees is established.
Similar species
Amanita citrina shares the abrupt rimmed bulb and the raw-potato odour but has a pale lemon-yellow to whitish cap and a white ring. Amanita brunnescens has a browner cap without the purple cast, flesh that stains reddish brown, and a bulb that splits into vertical clefts rather than staying rounded.
Amanita excelsa var. spissa is stouter, has a grooved ring, greyer veil patches, and a turnip-shaped bulb without a sharp rim. Amanita pantherina has a brown cap with pure white warts and a strongly grooved margin. Where the cap has been washed bare by rain, the grey ring and the abrupt rimmed bulb remain the most dependable characters.