Coccora

Amanita calyptroderma, widely known on the west coast as the coccora, is one of the largest and most striking amanitas of western North America. Mature caps commonly reach the size of a spread hand, coloured a rich orange-brown to coppery brown, and are often crowned with a single thick, felty white to buff sheet of universal veil that is far more substantial than the crumbly warts of most amanitas.

The species sits in the group of amanitas allied to the Caesar's mushrooms, characterised by a strongly lined cap margin, inamyloid spores, and a thick, persistent, sac-like volva at the stem base. The name Amanita lanei has been used for the same fungus in much of the older and some of the current literature, and the two names refer to one taxon in most modern accounts.

A closely related spring-fruiting species, Amanita vernicoccora, shares the shape and the volva but is pale yellow rather than orange-brown, so the season and the colour together separate the two.

Cap

Large, commonly 8-25 cm and occasionally wider, egg-shaped when young then convex to flat. The surface is deep orange-brown, coppery, or tawny, often paler and more yellow-buff towards the margin, slightly tacky when moist. The outer edge is distinctly grooved and lined for one to two centimetres. A thick, white to cream, felty or leathery patch of universal veil frequently remains on the disc as a single large sheet.

Gills

Free, crowded, white to cream or faintly yellowish, with a soft velvety look. Short gills are numerous and truncate.

Stipe

8-20 cm long and stout, white to pale cream, sometimes with faint tan banding. The ring is membranous, white to pale yellow, and hangs like a skirt from the upper stem, though it can flatten against the stem in age. The base sits in a thick, deep, white sac-like volva that is felty rather than fragile, and this cup is a defining character.

Flesh and spore print

Flesh white, thick, firm, unchanging when cut. Odour mild. The spore print is white; spores are ellipsoid and inamyloid, showing no blue-grey reaction in iodine, which separates this group from the amyloid-spored amanitas.

The coccora is a Pacific coast species, occurring from southern British Columbia through Washington and Oregon into California, and reaching well into the coastal and foothill woodlands of central and southern California. It forms mycorrhizal partnerships with Douglas-fir, tanoak, madrone, live oak, and other coastal broadleaf and conifer trees, and often fruits in the duff beneath dense canopy.

Fruiting is tied to the autumn and early winter rains, typically from October through January depending on latitude and elevation. Fruit bodies frequently push up half-buried in litter, appearing first as smooth white eggs before the volva ruptures and the orange cap emerges.

This is an ectomycorrhizal fungus that partners with a broad range of Pacific coast trees. The mycelium invests fine root tips with a fungal mantle and exchanges soil water, nitrogen, and phosphorus for tree sugars, and a single mycelial network can persist in the same grove for many years.

Its life cycle begins as a fully enclosed egg, in which the whole young fruit body is wrapped in the universal veil. As the stem elongates the veil ruptures, leaving the thick basal sac and, characteristically, one large sheet stuck to the cap. Free-falling spores from the gills are carried on air currents through the forest understorey, where they must meet a compatible host root to begin a new symbiosis.

Amanita vernicoccora is the closest match in structure but has a pale yellow to butter-coloured cap and fruits in spring rather than autumn. Amanita velosa is smaller, salmon-pink to pale orange, has an even more strongly grooved margin, and typically lacks a ring altogether.

Amanita muscaria in its western form has a red to orange cap covered with numerous small scattered warts and a bulb ringed by concentric belts of veil rather than a deep sac, and its margin is at most faintly lined. Amanita phalloides differs in its greenish, non-grooved cap and thinner, more fragile volva. Any amanita with a smooth unlined margin and a crumbly, powdery base can be separated from the coccora on those two features alone.