Moose Antlers Identification Guide

The Setting and the First Impression

Wynnea americana is one of the more theatrical fungi of eastern North American hardwood forest, and finding it is memorable. The setting is typically a shaded slope under oak, beech, maple or hickory, often with rhododendron or mountain laurel nearby, on humus-rich soil in mid to late summer. It is a fungus of the Appalachian belt and the surrounding uplands, with related species in eastern Asia.

The first impression is not of a mushroom at all. From a few metres away a cluster looks like a knot of dark leathery ears, or a set of small antlers, standing 5 to 15 cm out of the leaf litter. The individual arms are elongated, deeply cupped and inrolled, splayed outward from a common base, and the whole group has a rubbery, animal quality that separates it instantly from the caps and brackets around it.

Because it is an ascomycete rather than a gilled fungus, the identification routine is different. There is no cap, no gill, no stipe in the usual sense. Instead you read the shape of the cups, the two contrasting surfaces, the texture, and above all what is underneath the soil.

Reading the Fruit Body Shape

Start by counting and describing the arms. A cluster consists of several, commonly three to a dozen, elongated apothecia fused at the base into a single tough stalk-like mass. Each apothecium is spoon-, ear- or tongue-shaped, 4 to 13 cm tall and 2 to 5 cm wide, and narrows downward into a compressed stalk-like portion before merging with its neighbours.

The arms are deeply cupped and strongly inrolled along their long edges, so that each looks like a rolled leather ear rather than an open dish. They lean outward and often curve, giving the antler impression. Some clusters are neat and fan-like; others are crowded and irregular.

The key structural point is that this is one fungal individual producing many fused fertile arms, not a group of separate fruit bodies growing side by side. Test that by working a finger down to the base: the arms should be continuous with a single tough common stalk.

Reading the Two Surfaces

Every cup fungus has an inner fertile surface and an outer sterile one, and here they differ sharply, which is one of the strongest characters.

The inner, concave surface is the hymenium. It is smooth, matt to slightly waxy, and coloured a deep reddish brown, purplish brown, chocolate or almost blackish brown. In fresh material it looks damp and dark, and it may show fine wrinkling near the base.

The outer, convex surface is markedly paler and quite different in texture: rusty ochre, tawny, cinnamon or orange-brown, and distinctly roughened, covered in fine granules, warts or minute scurfy tufts that you can feel with a fingertip and see clearly with a hand lens. The contrast between the dark smooth inside and the paler granular outside is worth photographing on every collection.

With age both surfaces darken and the outer granulation flattens, so judge these characters on the freshest arms in the cluster.

The Sclerotium: the Character That Settles It

Do not stop at ground level. Excavate carefully with a trowel, working in a circle 10 to 15 cm out from the base and lifting the whole soil block, then tease the soil away by hand or in a stream of water.

Beneath the fused stalk you should find a sclerotium: a hard, irregular, tuber-like or lumpy underground body, blackish to dark brown on the outside, several centimetres across, firm and often incorporating soil, rootlets and leaf fragments into its surface. Cut it in half and the interior is paler, marbled, dense and tough.

This sclerotium is a nutrient storage organ that the fungus builds and then draws on to fund the large, fast-produced fruit body. Very few forest fungi of this general shape produce one, and finding it converts a probable identification into a confident one. Record its size, colour and texture in your notes; a collection without the base examined is much weaker evidence.

Flesh and Colour Change

Slice an arm across. The tissue is thick for a cup fungus, tough, rubbery and leathery-elastic, and it holds its shape rather than crumbling. It is pale brown to tan inside, sometimes with a slightly gelatinised layer beneath the hymenium visible as a darker band.

There is no latex, no milk and no dramatic bruising reaction. Cut surfaces may slowly darken a little on exposure but nothing rapid or vivid occurs. Dried material becomes hard, dark and horn-like, and rehydrates poorly, so take good field notes and photographs while the specimen is fresh.

Getting a Spore Deposit

Ascomycetes do not print the way gilled fungi do, but you can still obtain spores, and it is worth the effort because the spores here are unmistakable.

Cut an arm free, and either lay it hymenium-downward over a glass slide or stand it upright with a slide propped beside the concave face, then enclose the whole arrangement in a covered container with a damp paper towel. Leave it for a few hours at room temperature. Spores are shot actively from the asci, so they land on the slide as a fine dust, sometimes visible as a pale brownish film. A sharp change in humidity or a gentle breath across the surface often triggers a visible puff of spores.

Under the microscope the spores are large and distinctive: roughly 32 to 40 by 14 to 16 micrometres, ellipsoid to almond-shaped and usually pointed at both ends, brown, and ornamented with prominent longitudinal ribs or ridges running from end to end. Those lengthwise ribs on a large brown spore are effectively diagnostic in this group. The asci are cylindrical and eight-spored, and the paraphyses are slender and often curved at the tips.

Substrate, Season and Ecology

Fruit bodies arise from soil and humus in mature broadleaved forest, usually on shaded slopes with a deep litter layer, and are associated with oak, beech, maple, hickory and related trees, often in stands with a rhododendron understory. The season is summer into early autumn, mainly July through September, tied to warm weather with reliable rainfall.

The trophic status of the fungus is not settled. The presence of a sclerotium shows it accumulates and stores resources underground before fruiting, and the consistent association with particular forest types and tree species has prompted suggestions of a mycorrhizal relationship, while other evidence points toward decomposition of buried organic matter. It is best described honestly in the field notebook as a soil fungus of hardwood forest with an underground sclerotium, ecology uncertain.

It is a genuinely uncommon fungus with a patchy distribution, and it can fruit in one spot for several consecutive years because the sclerotium persists, so a known site is worth revisiting.

Separating It from the Look-alikes

Wynnea sparassoides is the closest relative and also produces a sclerotium. Its fruit body forms a rounded, crowded, cauliflower- or brain-like mass of shorter, more folded arms rather than a splayed set of long antler-like ears, and the individual lobes are broader and less deeply channelled.

Urnula craterium, the Devil's Urn, is a dark goblet-shaped ascomycete of similar toughness, but it fruits in early spring, is nearly black inside and out, has a single deep urn or cup rather than a cluster of elongated ears, is attached to buried hardwood sticks by black cords, and lacks a tuber-like sclerotium. Its spores are smooth.

Otidea species are ear-shaped and split down one side, which superficially matches, but they are much smaller and thinner, ochre-yellow to tan or brown throughout without a strongly contrasting granular exterior, they grow singly or in small scattered groups from litter, they have smooth spores, and there is no sclerotium.

Sarcoscypha and Microstoma species are bright scarlet inside, much smaller, and grow on buried sticks.

Gyromitra and other false morels have a lobed or brain-like fertile head on a distinct pale stalk, quite different in construction from a cluster of inrolled cups, and different spores.

Auricularia species are gelatinous, translucent, grow directly on wood, and collapse to a thin film when dry, whereas Wynnea is opaque, tough and soil-borne.

Quick Field Checklist

• Cluster of elongated, inrolled, ear- or antler-shaped arms fused at a common base
• Inner surface dark reddish to purplish brown and smooth; outer surface paler rusty ochre and granular
• Tough, rubbery, leathery flesh that holds its shape
• Hard blackish tuber-like sclerotium buried beneath the cluster
• Hardwood forest soil, mid to late summer; large brown spores with lengthwise ribs