Sarcoscypha coccinea

''Sarcoscypha coccinea'', commonly known as the scarlet elf cup, scarlet elf cap, or the scarlet cup, is a species of fungus in the family Sarcoscyphaceae of the order Pezizales. The fungus, widely distributed in the Northern Hemisphere, has been found in Africa, Asia, Europe, North and South America, and Australia. The type species of the genus '' Sarcoscypha'', ''S. coccinea'' has been known by many names since its first appearance in the scientific literature in 1772. Phylogenetic analysis shows the species to be most closely related to other ''Sarcoscypha'' species that contain numerous small oil droplets in their spores, such as the North Atlantic island species '' S. macaronesica''. Due to similar physical appearances and sometimes overlapping distributions, ''S. coccinea'' has often been confused with '' S. occidentalis'', '' S. austriaca'', and '' S. dudleyi''.

The saprobic fungus grows on decaying sticks and branches in damp spots on forest floors, generally buried under leaf litter or in the soil. The cup-shaped fruit bodies are usually produced during the cooler months of winter and early spring. The brilliant red interior of the cups—from which both the common and scientific names are derived—contrasts with the lighter-colored exterior. The edibility of the fruit bodies is well established, but its small size, small abundance tough texture and insubstantial fruitings would dissuade most people from collecting for the table. The fungus has been used medicinally by the Oneida Native Americans, and also as a colorful component of table decorations in England. In the northern part of Russia, where fruitings are more frequent, it is consumed in salads, fried with smetana, or just used as colored dressing for meals. ''Molliardiomyces eucoccinea'' is the name given to the imperfect form of the fungus that lacks a sexually reproductive stage in its life cycle.

Taxonomy, naming, and phylogeny

The species was originally named ''Helvella coccinea'' by the Italian naturalist Giovanni Antonio Scopoli in 1772. Other early names include ''Peziza coccinea'' (Nikolaus Joseph von Jacquin, 1774) and ''Peziza dichroa'' (Theodor Holmskjold, 1799). Although some authors in older literature have applied the generic name '' Plectania'' to the taxon following Karl Fuckel's 1870 name change (e.g. Seaver, 1928; Kanouse, 1948; Nannfeldt, 1949; Le Gal, 1953), that name is now used for a fungus with brownish-black fruit bodies. ''Sarcoscypha coccinea'' was given its current name by Jean Baptiste Émil Lambotte in 1889. Obligate synonyms (different names for the same species based on one type) include ''Lachnea coccinea'' Gillet (1880), ''Macroscyphus coccineus'' Gray (1821), and ''Peziza dichroa'' Holmskjold (1799). Taxonomic synonyms (different names for the same species, based on different types) include ''Peziza aurantia'' Schumacher (1803), ''Peziza aurantiaca'' Persoon (1822), ''Peziza coccinea'' Jacquin (1774), ''Helvella coccinea'' Schaeffer (1774), ''Lachnea coccinea'' Phillips (1887), ''Geopyxis coccinea'' Massee (1895), ''Sarcoscypha coccinea'' Saccardo ex Durand (1900), ''Plectania coccinea'' ( Fuckel ex Seaver), and ''Peziza cochleata'' Batsch (1783).

''Sarcoscypha coccinea'' is the type species of the genus ''Sarcoscypha'', having been first explicitly designated as such in 1931 by Frederick Clements and Cornelius Lott Shear. A 1990 publication revealed that the genus name ''Sarcoscypha'' had been used previously by Carl F. P. von Martius as the name of a tribe in the genus '' Peziza''; according to the rules of Botanical Nomenclature, this meant that the generic name ''Peziza'' had priority over ''Sarcoscypha''. To address the taxonomical dilemma, the genus name ''Sarcoscypha'' was conserved against ''Peziza'', with ''S. coccinea'' as the type species, to "avoid the creation of a new generic name for the scarlet cups and also to avoid the disadvantageous loss of a generic name widely used in the popular and scientific literature". The specific epithet ''coccinea'' is derived from the Latin word meaning "deep red". The species is commonly known as the "scarlet elf cup", the "scarlet elf cap", or the "scarlet cup fungus".

''S. coccinea'' var. ''jurana'' was described by Jean Boudier (1903) as a variety of the species having a brighter and more orange-colored fruit body, and with flattened or blunt-ended ascospores. Today it is known as the distinct species '' S. jurana''. ''S. coccinea'' var. ''albida'', named by George Edward Massee in 1903 (as ''Geopyxis coccinea'' var. ''albida''), has a cream-colored rather than red interior surface, but is otherwise identical to the typical variety.

Within the large area that includes the temperate to alpine-boreal zone of the Northern Hemisphere (Europe and North America), only ''S. coccinea'' had been recognized until the 1980s. However, it had been known since the early 1900s that there existed several macroscopically indistinguishable taxa with various microscopic differences: the distribution and number of oil droplets in fresh spores; germination behavior; and spore shape. Detailed analysis and comparison of fresh specimens revealed that what had been collectively called "''S. coccinea''" actually consisted of four distinct species: ''S. austriaca'', ''S. coccinea'', ''S. dudleyi'', and ''S. jurana''.

The phylogenetic relationships in the genus ''Sarcoscypha'' were analyzed by Francis Harrington in the late 1990s. Her cladistic analysis combined comparisons of the sequences of the internal transcribed spacer in the non-functional RNA with fifteen traditional morphological characteristics, such as spore features, fruit body shape, and degree of curliness of the "hairs" that form the tomentum. Based on her analysis, ''S. coccinea'' is part of a clade that includes the species ''S. austriaca'', ''S. macaronesica'', ''S. knixoniana'' and ''S. humberiana''. All of these ''Sarcoscypha'' species have numerous, small oil droplets in their spores. Its closest relative, ''S. macaronesica'', is found on the Canary Islands and Madeira; Harrington hypothesized that the most recent common ancestor of the two species originated in Europe and was later dispersed to the Macaronesian islands.

Description

Initially spherical, the fruit bodies are later shallowly saucer- or cup-shaped with rolled-in rims, and measure in diameter. The inner surface of the cup is deep red (fading to orange when dry) and smooth, while the outer surface is whitish and covered with a dense matted layer of tiny hairs (a tomentum). The stipe, when present, is stout and up to long (if deeply buried) by thick, and whitish, with a tomentum. Color variants of the fungus exist that have reduced or absent pigmentation; these forms may be orange, yellow, or even white (as in the variety ''albida''). In the Netherlands, white fruit bodies have been found growing in the polders.

''Sarcoscypha coccinea'' is one of several fungi whose fruit bodies have been noted to make a "puffing" sound—an audible manifestation of spore-discharge where thousands of asci simultaneously explode to release a cloud of spores.

Spores are 26–40 by 10–12  µm, elliptical, smooth, colorless, hyaline (translucent), and have small lipid droplets concentrated at either end. The droplets are refractive to light and visible with light microscopy. In older, dried specimens (such as herbarium material), the droplets may coalesce and hinder the identification of species. Depending on their geographical origin, the spores may have a delicate mucilaginous sheath or "envelope"; European specimens are devoid of an envelope while specimens from North America invariably have one.

The asci are long and cylindrical, and taper into a short stem-like base; they measure 300–375 by 14–16 µm. Although in most Pezizales all of the ascospores are formed simultaneously through delimitation by an inner and outer membrane, in ''S. coccinea'' the ascospores located in the basal parts of the ascus develop faster. The paraphyses (sterile filamentous hyphae present in the hymenium) are about 3 µm wide (and only slightly thickened at the apex), and contain red pigment granules.

Anamorph form

Anamorphic or imperfect fungi are those that seem to lack a sexual stage in their life cycle, and typically reproduce by the process of mitosis in structures called conidia. In some cases, the sexual stage—or teleomorph stage—is later identified, and a teleomorph-anamorph relationship is established between the species. The International Code of Nomenclature for algae, fungi, and plants permits the recognition of two (or more) names for one and the same organism, one based on the teleomorph, the other(s) restricted to the anamorph. The name of the anamorphic state of ''S. coccinea'' is ''Molliardiomyces eucoccinea'', first described by Marin Molliard in 1904. Molliard found the growth of the conidia to resemble those of the genera ''Coryne'' and '' Chlorosplenium'' rather than the Pezizaceae, and he considered that this suggested an affinity between ''Sarcoscypha'' and the family Helvellaceae. In 1972, John W. Paden again described the anamorph, but like Molliard, failed to give a complete description of the species. In 1984, Paden created a new genus he named ''Molliardiomyces'' to contain the anamorphic forms of several ''Sarcoscypha'' species, and set ''Molliardiomyces eucoccinea'' as the type species. This form produces colorless conidiophores (specialized stalks that bear conidia) that are usually irregularly branched, measuring 30–110 by 3.2–4.7 µm. The conidia are ellipsoidal to egg-shaped, smooth, translucent (hyaline), and 4.8–16.0 by 2.3–5.8 µm; they tend to accumulate in "mucilaginous masses".

Similar species

Similar species include '' S. dudleyi'' and '' S. austriaca'', and in the literature, confusion amongst the three is common. Examination of microscopic features is often required to definitively differentiate between the species. '' Sarcoscypha occidentalis'' has smaller cups (0.5–2.0 cm wide), a more pronounced stalk that is 1–3 cm long, and a smooth exterior surface. Unlike ''S. coccinea'', it is only found in the New World and in east and midwest North America, but not in the far west. It also occ