Armillaria ostoyae (Romagn.) Herink (illustrated 40% life size) Cap 3–15cm across, very variable, convex to shield-shaped; yellow-brown to tawny or dark brown, often with an olivaceous tinge; covered in darker, fibrillose scales, especially at the centre. Stem 60–150×5–15mm, often bulbous towards the base; yellowish, becoming reddish-brown at the base; initially with a thick, cottony, whitish to yellow ring. Flesh white; taste astringent, smell strong. Gills white, then yellowish, becoming pinkish-brown and often darker-spotted with age. Spores 8–9×5–6¼, elliptical. Spore print pale cream. Habitat in clusters on or around trunks or stumps of deciduous and coniferous trees or shrubs; summer to early winter. Common. Edible when cooked, but should only be eaten in small amounts, as it may cause stomach upsets and should possibly be considered poisonous. Some mycologists say that this is more likely to be poisonous than other Armillaria. Note in my first book this was named A. polymyces.
