Eyelash Cup Identification Guide

Where You Will Be Kneeling

This species is found at close range, on your knees, in wet places. The classic setting is a sodden, decorticated log lying in a stream bed or on a shaded flood terrace, waterlogged to the point where it squeezes when pressed. Other reliable settings are bare wet mud along a pond margin, a dripping bank beside a woodland track, a damp sawdust pile, a rotting plank in long grass, or moss-covered debris in a seepage.

What catches your eye is a scattering of small, intensely scarlet or orange-red spots on dark wet wood, often dozens of them in a troop, sometimes so crowded that neighbouring discs press against each other and go slightly polygonal. Individually they are only 2 to 15 mm across, so the colour does the work at distance and the structure does the work up close.

Before you touch anything, get your eye down to the level of the wood and look at the discs against the light. If the species is what you think it is, you will see a dark fringe standing up around each rim like a ring of tiny black bristles. That backlit silhouette is the fastest field confirmation there is.

The Disc

The fruitbody is an apothecium: a shallow cup that flattens with age. Young ones are distinctly cupped with an incurved rim; mature ones open out to a nearly flat or very slightly convex disc, sometimes with a wavy or lobed outline where crowding has distorted them.

The upper surface, the hymenium, is smooth, even and matte to slightly waxy, and coloured a bright scarlet, vermilion or orange-red. It is at its most vivid on fresh material in shade; strong sun and age drain it toward orange or dull brick. There is no stalk. The cup sits flat on the substrate, attached over a broad area of its base, and pries off with a knife point as a whole disc rather than lifting from a stem.

The Eyelashes

These give the species its name and they are worth studying properly with a hand lens.

Around the margin stands a dense fringe of stiff, straight, tapering hairs, dark brown to black, and in this species conspicuously long — up to about 1 to 1.5 mm, which is a substantial fraction of the width of a small disc. They point outward and slightly upward, and they are rigid enough to hold their shape when the cup is tilted. Shorter hairs of the same type are scattered over the outer surface of the cup, becoming sparser toward the base.

If you tease a fragment of the margin apart on a slide, the individual hairs are thick-walled, dark, pointed at the tip and divided by several cross-walls, and their bases are swollen and often forked or root-like where they anchor into the cup wall. Hair length, the number of cross-walls and the shape of the base are the characters that separate the many species in this genus, so it is worth measuring a few rather than eyeballing them.

Outer Surface, Flesh and Colour Change

Turn a disc over. The underside and outer flank are brownish to reddish-brown, duller than the hymenium and roughened by the scattered hairs. Where the cup met the substrate you will often find adhering wood fibres, mud or moss.

The flesh is extremely thin, brittle and reddish-brown, and a disc snapped in half breaks cleanly with no elasticity. There is no colour change on cutting, no bruising reaction and nothing exuded. The odour is negligible. The whole fruitbody dries down to a hard dark scab that rehydrates and resumes its shape when wetted, which is why a dried collection can be revived for later examination.

Getting the Spores

Cup fungi discharge their spores forcibly, which changes how you sample them. Two approaches work.

For a deposit, set a disc hymenium-side down over a slide or a piece of dark glass, cover it with a small container to keep the air still and humid, and leave it a few hours. The result is a faint whitish film, usually a diffuse patch rather than a sharp outline, because the spores are fired out at an angle.

For an immediate result, collect several discs, breathe warm damp air across them, and watch against a dark background: a synchronised discharge produces a visible white puff drifting off the surface. It is the most satisfying demonstration in ascomycete identification and takes seconds.

Under a microscope the spores are ellipsoid, colourless, roughly 17 to 22 by 10 to 14 micrometres, and their surface is ornamented with low, irregular warts rather than being smooth. Several oil droplets are usually visible inside. Ornamentation is best seen in a stain, and it is a primary character for placing a collection within the genus.

Substrate and Season

The fungus is a saprotroph of wet, rotting material. Its strongest preference is for sodden wood in an advanced state of decay, especially bark-free logs and planks lying in or beside water, but it also grows on wet bare soil, streamside mud, moss-covered debris, damp sawdust and occasionally on burnt or nutrient-enriched ground. The unifying requirement is persistent moisture; the species does not appear on dry substrates.

It fruits in troops rather than singly, and the season runs from spring through autumn, extending to year-round in mild maritime climates where the ground never dries out. It is widespread across the temperate Northern Hemisphere and reported broadly elsewhere. Look after rain, and look in the places rain drains toward.

Look-alikes and How to Break the Tie

Other Scutellinia species are the real problem, and there are many of them. They share the scarlet disc and the dark marginal hairs, and they are separated on hair length, hair base structure, and spore size and ornamentation. As a working rule, hairs consistently longer than 1 mm point to this species, while species such as S. umbrarum have shorter hairs on relatively larger discs and typically grow on soil. Treat a field determination as provisional unless you have measured hairs and spores.

Melastiza chateri looks similar in colour and grows on bare damp soil, but its hairs are short, pale brown and barely reach a third of a millimetre. Under a lens the margin looks finely fuzzy, not lashed; there is no black fringe silhouette against the light.

Aleuria aurantia is far larger, up to 10 cm, forms contorted, wavy, bright orange discs on compacted disturbed soil and path edges, and is completely hairless.

Cheilymenia species grow on dung and manured straw. They are hairy, but the hairs differ in structure and the substrate itself is a strong divider.

Anthracobia species occupy burnt ground, forming small orange-brown discs with sparse tufts of short brown hairs rather than a continuous marginal fringe.

Sarcoscypha species are deep, genuinely cup-shaped, stalked, much larger, grow on buried hardwood sticks in winter and early spring, and have a smooth or minutely white-downy outer surface with no dark lashes at all.

Octospora and Neottiella species associate with mosses, and their hairs are minute or absent; check whether the disc is emerging from a moss cushion and whether moss shoots around it look distorted.

Pyronema forms pinkish coalescing cushions on burnt ground with no defined discs and no hairs.