White Coral Identification Guide

The Setting and the First Glance

Autumn, damp woodland or an old grassy bank, and something in the moss that looks out of place: a small white sprig like a piece of sea coral or a plastic model of a bare shrub, standing 2-8 cm out of the green. That is the usual introduction to Ramariopsis kunzei.

The habitat range is wider than most coral fungi. You find it on mossy woodland floor under both conifers and broadleaves, along path edges and banks, in humus-rich leaf litter, and also in short grass, lawn edges and old unimproved pasture. What is constant is that it grows out of soil, moss or humus, never out of wood, and that detail alone removes several genera from consideration.

First Impression

A small, densely branched, evenly white tuft, brittle enough that a careless grab will shatter it. Height 2-8 cm and occasionally to 12; overall width up to about 5 cm. Fresh material looks faintly translucent and slightly waxy, and it stands upright rather than sprawling.

Reading the Branching Pattern

Work upward from the ground, because the branching architecture is where most of the identification lives.

The base is a short, sometimes almost non-existent common stem, whitish, occasionally with fine white down where it enters the moss. There is no thick fleshy trunk of the kind the big Ramaria species build.

From there the fruit body branches dichotomously or into several arms at once, repeating three to six times so that the count of tips is high relative to the size of the thing. Branches are slender, roughly 1-4 mm thick, round in cross-section, and smooth-walled: not flattened, not grooved, not wrinkled. The axils where two branches part are rounded and U-shaped rather than sharply V-shaped.

The tips are the key detail. They are blunt or slightly pointed, sometimes minutely forked into two or three small points, but they are never flattened into jagged crests, combs or crowns.

Colour is uniform from base to tip: pure white when fresh, ageing to cream, ivory or with a faint pinkish or buff cast in old material. There is no coloured tip zone, no yellow, no ochre and no lilac.

Flesh and Colour Change

Bend a branch. It snaps cleanly and audibly rather than bending, tearing or stretching, and the interior is white and homogeneous. The texture is brittle, not rubbery, not tough and not gelatinous.

There is no colour change on cutting, no bruising to brown or black, no latex and no exudate. Odour is indistinct. A total absence of reaction, on a fungus this white, is itself a useful data point.

Taking and Reading a Spore Print

The entire outer surface of the branches is fertile, so any part of the fruit body will print. Lay a whole specimen on its side on a sheet of paper, ideally with half over white and half over black, put it inside a covered box to hold humidity, and leave it overnight.

The print is white. This is the most important single test in the coral fungi, because it splits the white-spored genera, Ramariopsis, Clavulina, Clavaria and Clavulinopsis, from the true Ramaria, which drop yellow, ochre or rusty-brown spore masses in quantity and often dust their own lower branches with colour.

At x400 the spores of Ramariopsis kunzei are subglobose to broadly elliptical, roughly 3-5 micrometres, and minutely spiny or warted. Clavulina spores are smooth and larger, so a single microscope glance separates the two genera when the field characters leave you unsure.

Substrate and Season

The fungus fruits from soil, humus and moss, and is generally regarded as a litter saprotroph rather than a tree partner, although the ecology of the small corals is imperfectly known. It appears from midsummer through autumn, later into early winter in mild areas, singly, scattered or in small troops. Established patches tend to reappear in the same square metre of moss in successive years.

Damp, sheltered, mossy ground is the productive place to look, and a slow, low search is required because the fruit bodies are small and easily lost against pale litter.

Separating It from Look-alikes on Morphology Alone

Clavulina cristata, the crested coral, is the confusion that matters most. It is a similar size and also whitish, but its branches are noticeably thicker and often flattened rather than round, and its tips are jagged, crested and finely toothed rather than blunt. It commonly greys from the base upward with age, and it is very frequently blackened by the parasitic ascomycete Helminthosphaeria clavariarum, producing grey to charcoal lower branches. Ramariopsis kunzei stays white or cream and keeps blunt tips and round branches.

Clavulina rugosa is sparsely branched with a few thick, irregular, wrinkled or grooved arms and blunt ends, so the branch surface and the low branch count separate it.

Clavaria fragilis, the white spindles, is essentially unbranched: white cylindrical spindles in dense tufts, occasionally with one or two forks near the tip.

True Ramaria species are altogether bulkier and fleshier, with a thick solid base, and most carry yellow, tan, pinkish or lilac tones somewhere on the fruit body along with an ochre-yellow spore print.

Artomyces pyxidatus is the same general shape but grows on dead wood, usually fallen hardwood branches, and its branch tips end in a distinctive crown of points ringing a hollow centre.

Tremellodendron and some Sebacina species are tough and rubbery rather than brittle, with flattened branches that fuse together into sheets.

Coral-shaped slime moulds can mimic the outline at a glance but are soft, powdery when mature, and collapse rather than snapping.

A Practical Field Sequence

Confirm it is growing from soil, moss or litter and not from wood. Check the branches are round in section, slender and smooth-walled. Check the tips are blunt and not crested or crowned. Confirm uniform white to cream colour with no grey base and no coloured tips. Snap a branch and confirm brittle white flesh with no colour change. Print it overnight and confirm white, then check the spores for fine spines if a microscope is available.