Ochre Spreading Tooth

The Ochre Spreading Tooth belongs to Steccherinum, a genus of toothed crust fungi in the family Steccherinaceae. Instead of gills or pores, the fertile surface is drawn out into a dense pile of small spines — the same solution to increasing spore-bearing area found in the hedgehog fungi, but on a flat, wood-hugging fruitbody.

It is one of the most frequently encountered toothed crusts in temperate broadleaf woodland, forming long, brightly coloured patches on the undersides of dead branches. Where the wood surface curves upward, the crust often lifts free into a narrow shelf, making it effused-reflexed: part crust, part bracket.

Its warm salmon, apricot or ochre colouring is unusual among crusts and, combined with the fine even spines and the white woolly upper edge of any reflexed portion, makes it one of the more approachable resupinate species to name in the field.

Fruiting body

Spreading patches from two or three centimetres to well over 20 cm long, thin and leathery, closely attached to the wood but often lifting into narrow shelves 5–15 mm wide along the top edge of a branch. Several patches may fuse into a long ribbon.

Spines

The fertile surface is covered in crowded, slender, mostly conical spines 1–3 mm long, arranged in a dense even pile that flattens toward the margin. Colour is the key: bright ochre, apricot, salmon or pinkish-orange when fresh, fading to buff, straw or dull cream with age and drying.

Upper surface of reflexed parts

Where a shelf is formed, its upper face is whitish to pale cream, densely woolly or felted, and frequently marked with faint concentric zones, contrasting strongly with the coloured spines below.

Margin, flesh and spore print

The margin is thin, paler, fibrillose and often finely fringed. Flesh is very thin, tough and pale, sometimes with a faintly darker line visible in section. The spore deposit is white, and there is no colour change on bruising.

It grows on dead broadleaf wood — attached and fallen branches, twigs, small logs and worked timber — with beech, oak, hazel, ash, willow, maple and fruit trees among the frequent hosts. Occasionally it appears on conifer wood, but hardwood is the norm. It favours the shaded lower surfaces of branches lying in damp leaf litter.

The species is widespread through temperate Europe, Asia and North America. Fruitbodies form mainly from autumn into spring, and because the crust is tough and thin, patches persist and can be found dried and faded on the same branch throughout the year, reviving in colour after rain.

Steccherinum ochraceum is a saprotroph causing a white rot: it degrades lignin as well as cellulose, so the affected wood pales, softens and eventually becomes fibrous and stringy rather than cracking into cubes. This makes it part of the guild of fungi that fully mineralise fallen broadleaf branches.

It colonises small-diameter wood early in the decay sequence, frequently sharing a branch with other crusts and small brackets; the boundaries between competing mycelia can sometimes be seen as darker demarcation lines in the wood. Wind-dispersed spores from the spiny surface establish new colonies on freshly fallen or recently dead branches.

Steccherinum fimbriatum is thinner and smaller, greyish-lilac to pale buff rather than orange, with a conspicuously fringed, radiating margin. Radulomyces molaris has much coarser, blunter, more widely spaced teeth and stays cream to pale ochre, and grows mainly on dead oak. Dentipellis fragilis forms soft, brittle, pure white spine-covered patches with much longer spines.

Phlebia radiata shares the warm orange colouring but has a wrinkled, radially folded, waxy-gelatinous surface with no true spines. Mycoacia species are toothed and often yellowish, but their spines are more slender and cylindrical and their crusts lack the white woolly reflexed cap edge typical of the Ochre Spreading Tooth.