Wood hedgehog or Shingled hedgehog

The cap is 4-15 cm across and irregular, with an unevenly wavy margin. Convex when young, it flattens and spreads out with age, with a lumpy surface and a depressed centre. It's ivory, cream or ochre-yellow to light orange, turning reddish-brown in old mushrooms. The surface is dry and silky, like suede, and slightly sticky in wet weather. The cap skin is thin and peels easily.

The cap is 5–15 cm across and up to 25–30 cm in big specimens, and fleshy. It starts convex with an inrolled margin, then flattens, often with a dip in the middle, and in old caps the centre can open right down into the hollow stem. The margin becomes wavy with age.

The surface is dry, pale brown, buff or greyish brown, and covered in coarse dark brown to purplish brown scales. They sit in rings like roof tiles and get bigger and more upturned towards the centre. Young caps can be very pale, pinkish grey with small dark triangular scales.

The spines are the key diagnostic feature. The underside of the cap is densely packed with thin, pointed spines 3-6 mm long that break off easily. They're white to cream, yellowing with age and turning reddish-ochre in old mushrooms. The spore print is white.

Instead of gills there are crowded spines 0.5–1.5 cm long, brittle and running slightly down the stem. They are greyish white or pale lilac grey when young, turning greyish brown and purplish brown as the spores ripen. The spine layer comes away easily from the cap flesh.

The spore print is brown, which separates it from the Hydnum hedgehogs with their white print.

The stem is 3-8 cm tall and 1-3 cm thick, cylindrical, often widening toward the base, sometimes eccentric (off-centre from the cap). It's white to cream, yellowing slightly where pressed. The surface is smooth, with no ring. The stem flesh is firm, becoming spongy in old mushrooms.

The stem is short and thick, 3–8 cm tall and 1.5–4 cm wide, central or slightly off-centre, often widening towards the base. It's whitish to pale brown and browns from the base upwards. It's smooth apart from traces of stunted spines at the top, becomes hollow with age, and has white mycelium at the base. There is no ring and no volva.

The stem base is pale, with no green, blue or black colour outside or in the cut flesh. That's the feature that separates it from the bitter tooth fungi.

The flesh is thick, white, firm and brittle, and slowly turns pale ochre when cut (a slight yellowing). Young mushrooms have a delicate, pleasant nutty flavour; mature ones have a slightly bitter aftertaste that goes away after a brief boil.

The flesh is whitish to pale brown and soft, turning greyish brown in old specimens. It doesn't change colour when cut. The taste is mild in young mushrooms and bitter in old ones.

A faint, pleasant mushroomy-fruity smell with a hint of fresh nuts. The taste is mild and delicate, slightly bitter in old mushrooms.

Fresh mushrooms smell faint, of almost nothing. When fried or dried they develop a strong, spicy aroma, which is why the powder is prized as a seasoning.