Ruby Elfcup

Description

The ruby elfcup forms cup-shaped fruiting bodies 2–6 cm across. The inside of the cup is smooth and intensely red (faded to orange in dry weather), while the outside is whitish, covered with fine down. The stem, if present, is short and whitish. The flesh is thin and brittle.

It grows in winter and early spring, from December to May, on fallen, damp twigs of deciduous trees, often partly hidden in leaf litter or in the soil. In Poland it is a rare species, found in damp deciduous forests and thickets. Its intense red colour against the winter leaf litter is usually enough to catch the eye.

Similar species of the genus Sarcoscypha are practically indistinguishable macroscopically and can only be told apart under the microscope. The ruby elfcup is inedible. Because of its rarity, it is best left in the forest.

Identification features

Cap

Cup-shaped fruiting body, initially spherical, then shallowly saucer-shaped to cup-shaped with an incurved rim; diameter 2–6 cm (descriptions give different ranges). The inner surface is smooth, deep scarlet-red, fading to orange in dry weather. The outer surface is whitish to dirty ochre, covered with dense matted fine hairs. Forms with reduced or absent pigment exist: orange, yellow or white.

Hymenophore (underside of the cap)

No gills or tubes. The hymenial layer (spore-bearing asci) lines the smooth, red inner surface of the cup.

Stem

Often absent or very short; when present (especially in fruiting bodies growing from more deeply buried wood), it is stout, whitish, up to 4 cm long and 0.3–0.7 cm thick, covered with matted hairs.

Flesh

White, thin, brittle. No distinct smell or taste. The flesh should not be tasted.

Spore print and spores

Spore print white to colourless. Spores elongated-elliptical, smooth, colourless (hyaline), 26–40 × 10–12 µm, with small oil droplets gathered near both ends. Asci long, cylindrical, tapering to a short foot, about 300–375 × 14–16 µm. When spores are discharged from many asci at once, a faint "puff" may be heard and a small cloud of spores seen.

Habitat and distribution

Ecology. Saprotroph on dying, fallen twigs and wood of deciduous trees, often partly or completely buried in leaf litter or soil, in damp places. Recorded on rosaceous trees, beech, hazel, willow, elm, hornbeam, among others, and on oak in the Mediterranean region. Fruiting bodies grow singly or in groups; those growing from buried wood are larger than those on branches above ground. The fruiting bodies are persistent and in cool weather last several weeks.

Distribution. Northern Hemisphere: Europe, Asia, North America; also reported from Africa, Australia and South America. In Poland a rare species (some descriptions state that it does not occur), in deciduous forests and thickets; on the Red List of Plants and Fungi of Poland in category I (species of undetermined threat). Until 9 October 2014 under strict species protection, now removed from the list of protected species. In Europe species of the genus Sarcoscypha appear on red lists; in Great Britain the species has become very rare.

Fruiting. In Poland from December to May, most often from January to April; usually in the cool months of winter and early spring.

What can it be confused with?

• Sarcoscypha austriaca (Austrian elf cup) — Almost indistinguishable macroscopically; spores 29–36 × 12–15 µm, with an incomplete sheath and small caps at the ends. Separation requires a microscope.
• Sarcoscypha jurana — Fruiting body paler, more orange; spores flattened or bluntly ended. Protected in Poland (strict protection), not included in the Atlas; grows mainly on fallen lime (Tilia) twigs and is hard to tell apart in the field — do not pick red elf cups.
• Sarcoscypha dudleyi — Occurs in eastern North America; spores elliptical with rounded ends, 25–33 × 12–14 µm, completely enclosed in mucilage when young.
• Sarcoscypha macaronesica — A species of the Macaronesian islands; fruiting bodies smaller (up to 2 cm), spores smaller, about 20.5–28 × 7.3–11 µm.
• Scutellinia scutellata (eyelash cup) — Much smaller fruiting bodies with visible dark eyelashes on the rim, usually growing on damp wood and substrate.
• Plectania melastoma — Interior of the fruiting body orange-red, but the outer surface blackish, not whitish.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The name "coccinea" comes from the Latin word for deep red; in English the fungus is called the "scarlet elf cup".
• The red colour of the interior is produced by carotenoids, including plectaniaxanthin and β-carotene, stored in granules in the paraphyses.
• When spores are discharged at once from thousands of asci, the fruiting body may give off a faint "puff" and release a small cloud of spores.
• In Scarborough, England, the fruiting bodies were arranged on moss and leaves and sold as a table decoration.