Phaeolepiota aurea (Matt.) Konrad & Maubl. - Golden Bootleg

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

Phaeolepiota aurea, a rare species (Red Data listed, and so rare and probably threatened, but not a Biodiversity Action Plan or BAP species) generally referred to as Golden Bootleg or Golden Cap, is a large mushroom and very easy to spot; however, it is also easily overlooked because it bears a strong resemblance to another large but abundant species, the equally spectacular orange wood-rotting mushroom Gynopilus junonius.

The genus Phaeolepiota is monotypic, which means that it contains just this single species. There has been much debate as to whether this mushroom should be considered a member of the Agaricaceae (grouped with field mushrooms and their kin); some suggest it has more in common with Pholiota species, which belong to the family Strophariaceae.

Despite its attractive appearance and substantial proportions this rare mushroom is inedible and has been known to cause severe stomach upsets when eaten; it is known to contain hydrogen cyanide (hydrocyanic acid), which is seriously toxic to humans. Although in the past Phaeolepiota aurea was indeed listed as edible, this mushroom is no longer considered safe to eat. It's true that cooking reduces the concentration of the toxic acid, but it is still potentially quite dangerous. Shun this risky snack!

The specimens shown on this page were photographed in Wiltshire during October 2009.

Identification guide

	Cap The cap, and indeed initially the whole of the mushroom, is covered by a grainy sheath that eventually tears at the cap rim to form a pendent ring so substantial that it might better be described as a 'skirt' on the stem.Cap diameter at maturity is typically 8 to 20cm, exceptionally 30cm and rounded at first becoming almost flat with a small central umbo (a slight hump). In very dry weather caps can develop upturned wavy margins. The colour is usually orange-tan or golden brown, dry and granulose, and the margin is often fringed with veil fragments.
Gills	The adnate crowded gills have short decurrent teeth and are a pale golden colour, turning slightly darker with age.
Stem	10 to 20cm tall and typically 2 to 3cm across, the stipe increases in diameter towards the clavate (club-shaped) base. Above the ring, which persists through the life of the fruitbody, the stem is smooth and glossy and lighter in colour than the cap; below the ring the stem is striate and coloured much the same as the cap, with a similarly granulose surface.When cut, the light yellow stem flesh gradually darkens.
Spore print	Light yellow-brown
Odour/taste	Odour of bitter almonds (suggesting the presence of hydrocyanic acid); mild and slightly sweet taste.
Habitat	In groups beneath deciduous and coniferous trees on disturbed ground, often together with nettles.
Season	September to November
Occurrence	Rare and localised
Similar species	Gymnopilus junonius (syn. Gymnopilus spectabilis) is quite similar in appearance but does not have a grainy surface; its spores are much darker.

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.