False Death Cap
Amanita citrina
Also called citron amanita, false deathcap
A pale citron-yellow Amanita with flattened buff veil patches, a pendulous ring, an abruptly rimmed turnip-like basal bulb and a distinct raw-potato odour.
Overview
Amanita citrina is a common woodland Amanita of the Northern Hemisphere, placed in section Phalloideae alongside a small number of relatives that share a membranous ring, free white gills and a white spore print. Where most of that section has a sac-like volva, Amanita citrina departs from the pattern with a very different stem base: a swollen, abrupt, almost turnip-shaped bulb finished with a sharp free rim or gutter, rather than a loose bag.
In colour it is pale and rather washed out, ranging from lemon or citron yellow through greenish-cream to nearly white in the widespread var. alba. Its cap carries a few large, flattened, irregular buff to pale ochre patches of universal veil that lie flush with the surface instead of standing up as warts, and the margin is smooth rather than grooved.
The species is also one of the more reliably scented Amanita species. Cut flesh, particularly in the stem base, gives off a distinct earthy smell that is very widely described as raw potato or raw swede, and that odour combined with the rimmed bulb makes it straightforward to place once the whole fruit body has been lifted from the ground.
How to identify it
Cap
4-10 cm across, hemispherical at first, expanding to convex and then flat. The colour is pale citron-yellow to lemon, sometimes with greenish or olive tints, sometimes fading to cream or ivory, and in var. alba pure white throughout. The surface is smooth to slightly tacky in wet weather and bears a few large, thin, flat, irregular patches of universal veil in buff, pale ochre or dingy cream, which are flush with the cap rather than raised. The margin is even and not grooved.
Gills
Free from the stem or narrowly attached, crowded, white to pale cream and sometimes faintly yellowish near the edge. Many short gills are interspersed, and the edges are finely floccose. They remain pale at maturity.
Stipe
5-12 cm tall and 0.8-1.5 cm thick, white to pale yellow, smooth to faintly fibrillose, and carrying a persistent, membranous, pendulous ring high on the stem whose upper surface is often flushed yellowish and faintly grooved. The base swells abruptly into a large, rounded, turnip-like bulb finished with a distinct free rim or collar around its upper edge, the remains of the universal veil. There is no loose sac.
Flesh and spore print
The flesh is white and unchanging when cut, sometimes yellowish immediately beneath the cap skin. The odour of cut flesh, strongest in the bulb, is distinctly earthy and raw-potato-like. The spore print is white; the spores are almost round and stain blue-black in iodine reagents.
Where and when it grows
The false death cap grows on the ground in woodland, showing a strong preference for acidic, sandy or well-drained soils. It is frequent under beech and oak, common in birch woodland, and equally at home in pine and spruce plantations, making it one of the more catholic Amanita species in terms of host. It often appears in some abundance along woodland paths, on mossy banks and in the litter beneath closed canopy.
Fruiting runs from late summer through to late autumn, often persisting after many other woodland fungi have finished. The species is widespread and common across Europe and temperate Asia, and comparable material occurs widely in eastern North America, where similar pale Amanita species of the same group also grow under oak and pine.
Ecological role
Amanita citrina is ectomycorrhizal, forming a fungal mantle around the fine roots of its host trees and a network of hyphae between the outer root cells. Through this interface it delivers water, nitrogen and phosphorus drawn from a wide soil volume and receives photosynthetic carbon in return. Its tolerance of both broadleaf and coniferous hosts and of poor acidic soils explains why it is one of the most frequently encountered Amanita species in many temperate woodlands.
Development begins with a small egg-like button enclosed in a universal veil. Rather than tearing free as an intact sac, the veil in this species stays largely fused to the swelling stem base, which is why the mature fruit body shows a rimmed bulb with a narrow free collar rather than a loose bag, while the remaining veil tissue is carried upward as the flat patches on the cap. The partial veil over the gills is left behind as the ring.
Similar species
Amanita phalloides is the species most often confused with it and is separated by several structural features: its cap is olive-green, yellow-green or bronze with fine radial silky fibrils, it has a loose membranous sac-like volva rather than a rimmed bulb, its cap patches are usually absent, and it has a sweetish rather than potato-like odour. Amanita porphyria has the same abruptly rimmed bulb but a grey-brown to purplish-brown cap and a grey ring.
Amanita gemmata is warmer buff-yellow, has a faintly grooved cap margin at maturity, a thinner and often collapsing ring, and a smaller basal bulb with a narrow collar rather than an abrupt turnip shape. The white variety of Amanita citrina can suggest other pale Amanita species, but the rimmed bulb, flat cap patches and raw-potato odour of cut flesh keep it recognisable.