Description:
Cap: firm, convex usually with a central depression at maturity, dark olive-brown or dark greyish olive with a yellow-tawny, woolly margin when young which soon disappears, and the whole cap becomes sticky with age and turns deep purple when a drop of household ammonia is placed on it.
Stem: short, stout, similarly coloured to the cap except for the distinctly ochraceous apex, slimy and pitted.
Gills: crowded, cream-coloured to pale straw-coloured, but soon spotted with dirty brown, particularly when bruised.
Flesh: white or greyish ochre exuding a milk-like liquid which lacks a distinct smell and is white and unchanging when exposed to the air.
Spore-print: pale pinkish buff.
Spores: subglobose or ellipsoid and covered in a network of strongly developed, raised lines interconnected by finer ones, both of which stain blue-black in solutions containing iodine, generally 8 × 6 µm in size (7-8 × 6-7 µm).
Marginal cystidia: lance- or spindle-shaped and filled with oily contents.
Facial cystidia: similar to marginal cystidia.
Habitat & Distribution: Common in woods and copses, or on heaths especially in boggy places but always where birch is growing.