Rooting shankHymenopellis radicata

The rooting shank (Hymenopellis radicata), long known as Xerula or Oudemansiella radicata, is a tall woodland mushroom with a thin stem that carries on underground as a long, tapering 'root'. First Nature notes that it usually has as much of its stem below the forest floor as above. The root runs down to buried wood or tree roots, so the mushroom looks as if it grows straight out of the soil. The cap is slimy and wrinkled, the gills are white and widely spaced, and there's no ring. Richard Relhan first described it from Cambridgeshire in 1786.

How do you identify a rooting shank? The cap is 3 to 10 cm across, occasionally 12 cm, bell-shaped or convex at first, then flat with a broad central bump. It's slimy when wet, shiny when dry, and nearly always radially wrinkled or pitted, especially around the centre. The colour varies a lot: pale grey-brown, brown, ochre, olive-brown and sometimes almost white. The gills are white to cream, broad, thick and widely spaced, attached with a small tooth, and often brown-edged on old caps. The spore print is white. Above ground the stem is 8 to 20 cm tall and 0.3 to 1 cm thick, white at the top and brown lower down, grooved lengthways, often twisted and tough, with no ring and no veil at all. It swells slightly just above the root, and the root itself is pale again underground. To see the key feature, dig the mushroom up carefully rather than cutting it. The flesh is thin and white, soft in the cap and tough and fibrous in the stem. The smell is indistinct or faintly fruity.

Where does it grow? It rots buried dead wood and the roots of trees, mostly broadleaves, especially beech and oak, and occasionally turns up under conifers. It grows in woods and parks with old trees, singly or a few together. It fruits from summer to late autumn, most often in early to mid-autumn.

Is the rooting shank edible? Guides call it edible but not worth it: only the caps are eaten, as the stems are tough, and it rarely grows in any numbers. In Ukraine it's counted as conditionally edible and the caps are boiled first. We found no reports of poisoning. It isn't on lists of psilocybin mushrooms, and none of the descriptions we read mention psilocybin.

What can you mistake it for? The deer shield also has a brown cap and pale gills, but its gills are free and turn pink, its spore print is pink, and it grows on wood with no root. Its relative, the porcelain fungus, is also slimy with white, widely spaced gills, but it's white and translucent, has a ring and grows on dead beech trunks, not from the ground. Outside our catalogue, the usual mix-up is the whitelaced shank (Megacollybia platyphylla), which has a thicker stem that doesn't root deeply and white cords of mycelium at the base. Xerula pudens has a dry, velvety cap and a brown velvety stem. Remember that some brown mushrooms growing from soil are deadly, so don't pick unless you're sure.