Wood woollyfootGymnopus peronatus

The wood woollyfoot (Gymnopus peronatus) is one of the commonest small mushrooms of broadleaved leaf litter. Its giveaway is on the stem: the lower half is covered in dense white to yellowish woolly hairs, like a woolly sock, which also bind fallen leaves at the base. Its Latin name peronatus means 'wearing rough boots'. Recent studies move it to the genus Collybiopsis, but most guides still list it as Gymnopus or Collybia peronata. James Bolton described it from near Halifax in 1788.

How do you identify a wood woollyfoot? The cap is 2 to 7 cm across, usually 3 to 6 cm, convex with an inrolled margin at first, then flattening, sometimes with a low broad bump or a slight dip, and old caps have a wavy, wrinkled edge. It's hygrophanous, which means it changes colour as it dries. The colour varies a lot: pinkish cream, yellowish buff, ochre or reddish brown, darker in the centre. The gills are fairly widely spaced, narrow and almost free, pale yellowish at first and turning reddish brown with age. The stem is 3 to 8 cm tall and 0.3 to 0.8 cm thick, tough and hollow, cap-coloured or yellowish brown, paler at the top, with the woolly sock on the lower half. There's no ring. The spore print is white to pale cream. It has a burning, peppery taste, recorded in its old name Agaricus urens, 'burning', but there's no need to try it.

Where does it grow? In the leaf litter of beech and oak woods and under hedgerows, less often in needle litter in mixed and conifer woods and under bracken on heaths. It grows in groups and clusters, often in fairy rings and from a patch of bleached leaves. It fruits from summer to late autumn, most often in early to mid-autumn.

Is the wood woollyfoot edible? No, it isn't eaten: it's tough and burning-peppery. First Nature even calls it poisonous, and a 1948 study found it releases traces of hydrogen cyanide, although nobody has shown that this makes it dangerous. Don't treat it as safe.

What can you mistake it for? The fairy ring champignon grows in rings in grassland, has broader whitish gills and a pleasant smell, and no woolly base. The deceiver has thick, pinkish, widely spaced gills and a fibrous stem without the white sock. The russet toughshank has crowded white gills that don't turn reddish brown. The real danger is deadly brown mushrooms, because the gills of an old woollyfoot turn reddish brown and can look 'brown-spored'. A spore print tells it apart from the funeral bell, webcaps and fibrecaps (white for the woollyfoot, brown for them), but not from the deadly dapperling, which is also white-spored; tell that one by its scales and ring zone. The funeral bell has a rusty-brown spore print, a ring or ring zone and grows on wood, including wood buried under the litter. The deadly webcap and the fool's webcap have a cobweb veil and rusty-brown spores. Fibrecaps such as the deadly fibrecap have fibrous caps and clay-brown spores. The deadly dapperling (Lepiota brunneoincarnata) is small, with scales on the cap, white gills and a ring zone. Funeral bell and dapperling poisoning gives the first symptoms only 6 to 24 hours after eating, and webcap poisoning later still, after two or three days or more. If someone may have eaten a small brown mushroom, get help straight away, even if they feel fine: call emergency services on 112 (999 in the UK) or your local poison centre and keep any leftovers.