Crested Coral Identification Guide

First Impressions and the Setting

Clavulina coralloides, the Crested Coral, is one of the most frequently encountered coral fungi in temperate woodland, and it usually turns up in the same sorts of places: along the sides of woodland paths, on mossy banks, on thin soil over tree roots and among leaf litter in both broadleaf and conifer woods. It fruits from soil rather than from wood and is mycorrhizal, so it appears in established woodland rather than on stumps or logs. From a standing position it looks like a small clump of white or off-white coral, two to eight centimetres tall and about as wide, sitting low against dark litter or green moss. Individual clumps often occur in numbers along a track edge, and once you have got your eye in you will see them repeatedly on the same walk. The whiteness is the first impression, though it is rarely a pure white: expect cream, ivory or greyish-white, and often a clump where the lower half has gone distinctly grey while the tips remain pale.

Reading the Overall Structure

Examine the architecture before anything else. The fruiting body arises from a single short, stout, whitish base a few millimetres across, which divides almost immediately and then repeatedly into slender, upright, somewhat flattened or rounded branches. Branching is dense and irregular, not neatly dichotomous throughout, and the whole clump has a bushy, cauliflower-like or antler-like outline rather than a fan or a simple club. Branches are typically 2 to 5 millimetres thick, smooth-sided, sometimes slightly grooved or channelled, and they may fuse or press together where crowded. The clump is soft and slightly flexible when fresh but snaps cleanly when bent sharply, and there is no distinct stipe and cap arrangement at all.

The Branch Tips

The tips are the character in the name and the single best field mark. Bring the clump close, use a hand lens, and look at the ends of the branches. In this species each branch terminates not in a blunt club, a single point or a smooth fork, but in a cluster of several fine, sharp, irregular teeth, arranged like a tiny crown, comb or cockscomb. The effect is fringed and crested, and on a good specimen every tip in the clump is finished this way. Compare that with the blunt, rounded or simply forked tips of most other white corals. If the tips are worn or the specimen is old the crests may be reduced, so choose a fresh, fully grown clump for this check.

The Fertile Surface and Flesh

Unlike an agaric, a coral fungus carries its spore-producing layer on the outside of the branches, and there is no separate gill, pore or tooth surface to examine. The fertile layer covers the flanks and upper parts of the branches evenly and is not visually distinct from the sterile base. Break a branch across: the flesh is white, solid, slightly waxy and rather brittle. It does not change colour on breaking, does not exude latex and does not bruise to a different shade, though handled areas may dull slightly. The smell is faint and unremarkable, mushroomy or slightly earthy. If your clump is grey or blackish in its lower parts and white at the tips, note it but do not discard the identification, because that pattern is caused by a small parasitic ascomycete, Helminthosphaeria clavariarum, that commonly colonises this species and darkens the branches from the base upwards.

Taking a Spore Print

Corals produce spores freely, and getting a print is easier than it looks. Cut the clump off at the base and stand it upright in a small blob of modelling clay on a sheet of black paper, or simply lay a well-branched clump on its side on the paper. Cover it with a bowl and leave it in a still place overnight. The deposit forms as a white to very pale cream dusting, sometimes only visible when you tilt the paper against the light, which is why dark paper matters. The pure white print rules out a large part of the coral fungus field in one step. Under the microscope this genus has an unusual and diagnostic feature: the basidia bear only two sterigmata rather than the usual four, and the spores are broadly ellipsoid to almost spherical, smooth, and comparatively large at roughly 7 to 11 by 6.5 to 10 micrometres.

Substrate, Habitat and Season

This is a terrestrial, mycorrhizal fungus of woodland soils, associating with a range of broadleaf and coniferous trees including beech, oak, birch, spruce and pine. It tolerates a wide span of soil types and is as happy on mossy acid banks as on chalky path edges. It fruits from mid summer through to late autumn, peaking in the wetter months, and often reappears in exactly the same spot in successive years. Being terrestrial matters for identification: a coral fungus arising directly from a log, stump or buried branch belongs elsewhere.

Separating the Closest Look-alikes

Clavulina cinerea is the nearest relative and the commonest source of confusion. It is uniformly grey to ash-grey or slightly lilac-grey throughout including the tips, with thicker, blunter, more rounded branch ends and generally less dense branching. The complication is that greyed, parasitised Crested Coral looks similar, so check the tips: even a heavily discoloured Crested Coral usually keeps finely toothed crests, whereas Clavulina cinerea has blunt tips even when fresh.

Clavulina rugosa is white like the Crested Coral, but it is mostly unbranched or only sparsely and irregularly branched, forming thick, wrinkled, contorted clubs with a rough, longitudinally furrowed surface and blunt tips.

Ramaria species are the other main group. They are usually larger and fleshier, coloured ochre, yellow, tan, pinkish or violet, arise from a substantial fleshy base, and crucially give an ochre-yellow to brownish spore print. Their spores are warted or striate rather than smooth.

Artomyces pyxidatus grows on dead wood, not soil, and its branch tips are distinctive crowns with a hollow cup and a ring of points around the rim, a quite different geometry from the fine even teeth here.

Tremellodendron and Sebacina species are tougher and more gelatinous, with flattened, fused, fan-like branches and blunt margins.

Clavaria and Clavulinopsis species are usually simple unbranched clubs or spindles, often in bright yellow, orange or violet, growing in grassland rather than in woodland litter.

Field Checklist

• White to cream branched coral, 2 to 8 centimetres tall, on woodland soil
• Dense, irregular, bushy branching from a short common base
• Branch tips finished with fine, sharp, crested teeth
• White brittle flesh with no colour change on breaking
• Frequently greyed or blackened from the base upwards by a parasitic ascomycete
• White spore print, basidia with two sterigmata
• Path edges, mossy banks and litter in broadleaf and conifer woods, summer to late autumn