Agaricus osecanus

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Agaricus osecanus

In a church yard. 29 October 2020 Hampshire. Photograph copyright Leif Goodwin

Synonymns

Agaricus nivescens

Cap

Convex, expanding with age, smooth or radially fibrous, sometimes splitting radially, often with ring remnants attached to the margin, white, slightly brown or ochraceous with age, about 7 to 16 cm across

Gills

Broad, crowded, free, pinkish, then chocolate brown finally dark brown

Stem

Equal, often tapered at the base, sometimes bent, white, sometimes pinkish above the ring, ring large forming a double cog wheel pattern

Flesh

White, firm

Smell

Pleasant, sweetish, variously described as aniseed, almond or mushroom

Taste

Mushroomy

Season

Autumn

Distribution

Rarely reported but probably frequent

Habitat

On soil with grass, or on dunes

Spore Print

Dark brown

Microscopic Features

Spores ellipsoidal, smooth (6-7) x (4-5) µm2. Basidia club shaped, 4 spored. Gill edge cystidia club shaped, cylindrical or globose.

Edibility

Edible, good

Notes

The cap surface turns lemon yellow when a dop of KOH solution is applied. This is a characteristic of Agaricus species in the Arvenses, Minores and Xanthodermati groups. This species is closely related to A. arvensis. It is separated by weakly or non yellowing flesh, a fainter smell and smaller spores. Some authorities treat this species as synonymous with Agaricus arvensis.

Additional Photographs

Agaricus osecanus

Spores in Congo Red solution viewed with a x100 immersion objective. 29 October 2020 Hampshire. Photograph copyright Leif Goodwin

Agaricus osecanus

Gill edge in Congo Red solution viewed with a x40 objective. 29 October 2020 Hampshire. Photograph copyright Leif Goodwin