Agaricus xanthodermus Genevier syn. Psalliota xanthoderma (Genevier) Richon & Roze. Yellow Stainer, Agaric jaunissant, Giftchampignon, Agarico giallescente, Karbolchampignon, Sárguló csiperke, karbol-szagú csiperke. Cap 5–15cm across, subspherical with the top flattened later expanded convex, white at first later often with tiny indistinct greyish-brown scales and bruising bright chrome-yellow, especially towards the margin. Stem 50–150 x 10–20mm, white, bulbous at the base; ring white with a thickened edge which can cause it to appear double. Flesh white, staining chrome-yellow in the stem base. Taste slightly unpleasant, smell slightly of ink. Gills white at first then pale pink, finally grey-brown. Cheilocystidia thin-walled, sub-globose or ovate, hyaline, 10–20 x 8–14µ. Spore print purple-brown. Spores ellipsoid, 5–6.5 x 3–4µ. Habitat in woods, meadows and gardens. Season summer to autumn. Occasional. Poisonous. The symptoms are sweating, flushing and severe stomach cramps, but only some people are affected. Distribution, America and Europe.