Scarlet Elf Cup Identification Guide

Where you will be standing

This is a late-winter and early-spring find, and the setting is nearly as diagnostic as the fungus. The wood is bare, the ground is saturated, and you are following a stream side, a wet flush or a damp hollow where fallen branches lie half sunk in moss and silt. The find registers as an impossible splash of pillar-box red at ground level, often the only strong colour in the entire scene. Cups usually appear in loose troops of three to a dozen along a single buried branch, so if you find one, trace the line of the stick with your eye and you will normally find its neighbours.

Before touching anything, note two things: the cups are sitting on or around dead wood rather than on bare mineral soil, and the substrate is broadleaf, not conifer. Both matter later.

Reading the cup

The fruitbody is a disc or shallow bowl 1 to 5 cm across, occasionally to 7 cm in a well-fed colony. Young ones are deeply cupped with a strongly inrolled rim; as they expand they flatten, and old ones often become saucer-like or split and buckle irregularly at the margin. The inner face, which is the fertile hymenium, is scarlet to vermilion, sometimes deepening towards blood-red in cold weather and occasionally fading to orange in exposed positions. Rare colour forms are pale pink or white; those are still the same species and everything else about them holds.

The inner surface is smooth, matt to faintly waxy, and slightly uneven or wrinkled towards the base of the cup. It is not gelatinous and it does not glisten as a jelly fungus does.

The outer surface, the character most people skip

Turn the cup over. This is the observation that separates the group from the other red cup fungi at a glance. The exterior is a completely different colour from the interior: whitish, pale pinkish-buff or cream, and it is densely covered with a fine matted felt of short hairs. With a lens the felt resolves into a dense tomentum rather than the coarse bristles you get on an eyelash cup. Run a fingertip over it and it feels soft and slightly suede-like, and it is often dirtied with silt because the cups sit low.

Stalk and attachment

Most cups have a short stalk, from a few millimetres to 3 cm, whitish and downy like the exterior, and it is usually buried in moss or leaf litter so that the cup appears to sit directly on the ground. Lift carefully with a knife rather than pulling. The stalk should lead down to a fallen twig or branch, generally with the bark already stripped or rotted off, buried in wet litter and soft enough to dent with a thumbnail. Establishing that wood attachment is a required step, not an optional one.

Flesh in section

Cut a cup vertically. The flesh is thin, 1 to 2 mm, firm and slightly rubbery-elastic rather than brittle, whitish to pale pink, and it does not change colour on cutting. The red pigment is essentially confined to the upper fertile layer, so a cross-section shows a thin red skin over a white body, which is a useful photograph for records.

Spores: the puff test and the print

Cups of this group discharge their ascospores explosively and in synchrony. Warm a fresh cup in your hand for a minute and breathe gently across the disc: a fine white cloud of spores puffs off the surface, sometimes with a faint hiss. It is one of the most satisfying demonstrations in the winter woods and it confirms you are dealing with a cup fungus rather than a lichen or a slime mould.

For a deposit, rest the cup face-down over a slide inside a covered box for a few hours; the print is whitish. Under the microscope the ascospores are large, ellipsoid, smooth and hyaline, roughly 26 to 40 by 10 to 14 micrometres, and in this species they typically have rounded ends and scattered small oil droplets rather than a pair of large polar ones.

Substrate and season

December to April is the core window, with a peak in February and March, and it is one of the very few conspicuous fungi fruiting in that period. It grows on damp, decorticated fallen hardwood, with willow by far the most frequent host, followed by hazel, elm, maple, beech and alder. Wet woodland, stream banks, carr, hedge bottoms with a ditch and shaded damp copses are all productive. Constant moisture matters more than the exact tree species: sticks lying in mossy silt where water sits produce far more cups than sticks on a dry bank.

Look-alikes on structure alone

• Sarcoscypha coccinea: macroscopically almost identical, and honest recording treats the two as a pair. The separation rests on the hairs of the outer surface, which are strongly coiled and corkscrew-like in austriaca and straighter or merely wavy in coccinea, and on spore detail. On field characters alone, record the aggregate.
• Sarcoscypha jurana: associated with lime (Tilia), the disc more orange-scarlet, and the spores larger.
• Orange Peel Fungus, Aleuria aurantia: bright orange rather than scarlet, autumnal, growing directly on bare compacted soil, gravel paths and track edges; brittle rather than elastic, essentially stalkless, and with no downy pale exterior.
• Caloscypha fulgens: a spring conifer-forest species near melting snow, yellow-orange, and it stains blue-green where handled or along the margin, a change this species never shows.
• Microstoma protractum: a deeper, narrower goblet on a long slender stalk, with the margin split into pointed teeth, on buried hazel and oak in spring.
• Scutellinia species, the eyelash cups: much smaller, orange-red, flat, and fringed with stiff dark brown bristles that are obvious with a lens.
• Melastiza chateri: small, orange, on bare damp soil, with short brown marginal hairs and no distinct stalk.
• Plectania and Pseudoplectania: same cup architecture but black or blackish-brown throughout.

Field sequence

Season and setting narrow it to a handful of possibilities before you kneel. Scarlet interior plus a pale downy exterior plus a short stalk running to buried hardwood gets you to the genus with confidence. The final split between the two common scarlet species needs a lens on the exterior hairs at high magnification, so collect a small dried fragment if you want to take the record further, and note the host tree while you are still standing over it.