Lactam piperata

Lactam piperata (ly.) Pers. Tent. Disp. Fung. 64. 1797
Agaricits piperatus L. Sp. PI. 1173. 1753. Agaricus Listeri With. Brit. PI. ed. 2. 3 : 288. 1792.
Pileus fleshy, convex-umbilicate, at length infundibuliform, 4-12 cm. or more in diameter ; surface white, azonate, dry, glabrous ; margin involute at first and naked, at length uplifted : context compact, white, unchanging or becoming sordid, edible ; latex white, unchanging, very acrid, abundant; lamellae white or creamywhite, forking dichotomously, close, more or less decurrent, arcuate at first, then extending upwards, only about 2 mm. broad; stipe white, equal, dry, often pruinose, solid and firm, 2-8 cm. long, up to 2 cm. thick : spores white, subglobose, nearly smooth, 8-9 /^ in diameter.
Type LOCALITY : Sweden.
Habitat : Oak woods or groves.
Distribution : Temperate North America and Europe.