Pearly Powdercap

The fruiting body of Cystoderma carcharias is a relatively small agaric. The fruiting body is characterised by an off-white and pale pink-tinged cap with a distinct darker central spot, and a powdery cuticle. The cap is at first convex, but with maturity becomes flat and slightly umbonate. The cap is up to 6 cm (2.4 in) in diameter and may bear a margin fringed with remnants of a partial veil. The gills are white, adnate and crowded. The stem is white and smooth above, and granular below a white, upturned, flared and persistent ring. The stem is cylindrical and up to 7 cm (2.8 in) tall. The flesh is white, firm and full throughout. Additionally, C. carcharias forma album is a form recognised as having a snow-white cap. Under a microscope, the spores are ellipsoid, with dimensions 4–5.5 by 3–4 μm. The spores are white and amyloid. The basidia are 4-spored, club-shaped, and measure 20–25 by 4–6 μm. The fruiting body of C. carcharias bears a characteristic strong, unpleasant odour. The odour has been described as earthy, muddy and mouldy by various authors. This has been attributed to the presence of the compound geosmin. The taste is not distinctive. Cystoderma carcharias is a fairly common fungus distributed in Europe, North America and temperate Asia, typically occurring in coniferous forests. It has also been found on the treeless, Australian subantarctic Macquarie Island. …